fastapi_core/

testing.rs

//! Test utilities for fastapi applications.
//!
//! This module provides a [`TestClient`] for in-process testing of handlers
//! without network overhead. It integrates with asupersync's capability model
//! and supports deterministic testing via the Lab runtime.
//!
//! # Features
//!
//! - **In-process testing**: No network I/O, fast execution
//! - **HTTP-like API**: Familiar `client.get("/path")` interface
//! - **Request builder**: Fluent API for headers, body, cookies
//! - **Response assertions**: Convenient assertion helpers
//! - **Cookie jar**: Automatic session management across requests
//! - **Lab integration**: Deterministic testing with asupersync
//!
//! # Example
//!
//! ```ignore
//! use fastapi_core::testing::TestClient;
//! use fastapi_core::middleware::Handler;
//!
//! async fn hello_handler(ctx: &RequestContext, req: &mut Request) -> Response {
//!     Response::ok().body(ResponseBody::Bytes(b"Hello, World!".to_vec()))
//! }
//!
//! #[test]
//! fn test_hello() {
//!     let client = TestClient::new(hello_handler);
//!     let response = client.get("/hello").send();
//!
//!     assert_eq!(response.status().as_u16(), 200);
//!     assert_eq!(response.text(), "Hello, World!");
//! }
//! ```
//!
//! # Deterministic Testing
//!
//! For reproducible tests involving concurrency, use [`TestClient::with_seed`]:
//!
//! ```ignore
//! let client = TestClient::with_seed(handler, 42);
//! // Same seed = same execution order for concurrent operations
//! ```

use parking_lot::Mutex;
use std::collections::HashMap;
use std::future::Future;
use std::sync::Arc;

use asupersync::Cx;

use crate::context::RequestContext;
use crate::dependency::{DependencyOverrides, FromDependency};
use crate::middleware::Handler;
use crate::request::{Body, Method, Request};
use crate::response::{Response, ResponseBody, StatusCode};

/// A simple cookie jar for maintaining cookies across requests.
///
/// Cookies are stored as name-value pairs and automatically
/// added to subsequent requests.
#[derive(Debug, Clone, Default)]
pub struct CookieJar {
    cookies: Vec<StoredCookie>,
    next_id: u64,
}

#[derive(Debug, Clone, Copy, PartialEq, Eq)]
enum CookieSameSite {
    Lax,
    Strict,
    None,
}

#[derive(Debug, Clone, PartialEq, Eq)]
enum CookieDomain {
    /// Unscoped cookies are always sent (used by manual `CookieJar::set()`).
    Any,
    /// Host-only cookie (Domain attribute not present).
    HostOnly(String),
    /// Domain cookie (Domain attribute present).
    Domain(String),
}

#[derive(Debug, Clone)]
struct StoredCookie {
    id: u64,
    name: String,
    value: String,
    domain: CookieDomain,
    path: String,
    secure: bool,
    #[allow(dead_code)]
    http_only: bool,
    #[allow(dead_code)]
    same_site: Option<CookieSameSite>,
    expires_at: Option<std::time::SystemTime>,
}

impl CookieJar {
    /// Creates an empty cookie jar.
    #[must_use]
    pub fn new() -> Self {
        Self::default()
    }

    /// Sets a cookie in the jar.
    pub fn set(&mut self, name: impl Into<String>, value: impl Into<String>) {
        let name = name.into();
        let value = value.into();

        // Preserve previous semantics: manual `set()` behaves like a single cookie per name.
        self.cookies
            .retain(|c| !(c.name == name && c.domain == CookieDomain::Any));

        let id = self.next_id;
        self.next_id = self.next_id.wrapping_add(1);
        self.cookies.push(StoredCookie {
            id,
            name,
            value,
            domain: CookieDomain::Any,
            path: "/".to_string(),
            secure: false,
            http_only: false,
            same_site: None,
            expires_at: None,
        });
    }

    /// Gets a cookie value by name.
    #[must_use]
    pub fn get(&self, name: &str) -> Option<&str> {
        self.cookies
            .iter()
            .filter(|c| c.name == name)
            .max_by_key(|c| c.id)
            .map(|c| c.value.as_str())
    }

    /// Removes a cookie from the jar.
    pub fn remove(&mut self, name: &str) -> Option<String> {
        let mut removed: Option<String> = None;
        self.cookies.retain(|c| {
            if c.name == name {
                removed = Some(c.value.clone());
                false
            } else {
                true
            }
        });
        removed
    }

    /// Clears all cookies from the jar.
    pub fn clear(&mut self) {
        self.cookies.clear();
        self.next_id = 0;
    }

    /// Returns the number of cookies in the jar.
    #[must_use]
    pub fn len(&self) -> usize {
        self.cookies.len()
    }

    /// Returns `true` if the jar is empty.
    #[must_use]
    pub fn is_empty(&self) -> bool {
        self.cookies.is_empty()
    }

    /// Formats cookies for the Cookie header.
    #[must_use]
    pub fn to_cookie_header(&self) -> Option<String> {
        let mut by_name: HashMap<&str, &StoredCookie> = HashMap::new();
        for c in &self.cookies {
            match by_name.get(c.name.as_str()) {
                Some(existing) if existing.id >= c.id => {}
                _ => {
                    by_name.insert(c.name.as_str(), c);
                }
            }
        }

        if by_name.is_empty() {
            return None;
        }

        Some(
            by_name
                .into_values()
                .map(|c| format!("{}={}", c.name, c.value))
                .collect::<Vec<_>>()
                .join("; "),
        )
    }

    /// Formats cookies for the Cookie header for a specific request.
    ///
    /// This applies the cookie matching rules needed for session persistence:
    /// domain, path, secure, and expiration.
    #[must_use]
    pub fn cookie_header_for_request(&self, request: &Request) -> Option<String> {
        let host = request_host(request);
        let path = request.path();
        let is_secure = request_is_secure(request);
        let now = std::time::SystemTime::now();

        // Select one cookie per name using path length (more specific wins), then newest.
        let mut selected: HashMap<&str, &StoredCookie> = HashMap::new();
        for c in &self.cookies {
            if c.secure && !is_secure {
                continue;
            }
            if let Some(exp) = c.expires_at {
                if exp <= now {
                    continue;
                }
            }
            if !domain_matches(&c.domain, host.as_deref()) {
                continue;
            }
            if !path_matches(&c.path, path) {
                continue;
            }

            match selected.get(c.name.as_str()) {
                None => {
                    selected.insert(c.name.as_str(), c);
                }
                Some(existing) => {
                    let a = (c.path.len(), c.id);
                    let b = (existing.path.len(), existing.id);
                    if a > b {
                        selected.insert(c.name.as_str(), c);
                    }
                }
            }
        }

        if selected.is_empty() {
            return None;
        }

        Some(
            selected
                .into_values()
                .map(|c| format!("{}={}", c.name, c.value))
                .collect::<Vec<_>>()
                .join("; "),
        )
    }

    /// Parses a Set-Cookie header and updates the jar.
    pub fn parse_set_cookie(&mut self, request: &Request, header_value: &[u8]) {
        let Ok(value) = std::str::from_utf8(header_value) else {
            return;
        };
        self.parse_set_cookie_str(request, value);
    }

    fn parse_set_cookie_str(&mut self, request: &Request, value: &str) {
        let mut parts = value.split(';');
        let Some((name, val)) = parse_cookie_name_value(parts.next()) else {
            return;
        };

        let host = request_host(request);
        let attrs = parse_set_cookie_attrs(parts);

        let Some(domain) = cookie_domain_for_set_cookie(host.as_deref(), attrs.domain) else {
            return;
        };

        let path = attrs
            .path
            .unwrap_or_else(|| default_cookie_path(request.path()));

        let expires_at = match compute_cookie_expiration(attrs.max_age, attrs.expires_at) {
            CookieExpiration::Delete => {
                self.remove_by_key(name, &domain, &path);
                return;
            }
            CookieExpiration::Keep(expires_at) => expires_at,
        };

        let id = self.next_id;
        self.next_id = self.next_id.wrapping_add(1);
        self.upsert(StoredCookie {
            id,
            name: name.to_string(),
            value: val.to_string(),
            domain,
            path,
            secure: attrs.secure,
            http_only: attrs.http_only,
            same_site: attrs.same_site,
            expires_at,
        });
    }

    fn remove_by_key(&mut self, name: &str, domain: &CookieDomain, path: &str) {
        self.cookies
            .retain(|c| !(c.name == name && &c.domain == domain && c.path == path));
    }

    fn upsert(&mut self, cookie: StoredCookie) {
        // Replace existing cookie with same (name, domain, path), otherwise insert.
        for existing in &mut self.cookies {
            if existing.name == cookie.name
                && existing.domain == cookie.domain
                && existing.path == cookie.path
            {
                *existing = cookie;
                return;
            }
        }
        self.cookies.push(cookie);
    }
}

#[derive(Debug, Default)]
struct SetCookieAttrs {
    domain: Option<String>,
    path: Option<String>,
    max_age: Option<i64>,
    secure: bool,
    http_only: bool,
    same_site: Option<CookieSameSite>,
    expires_at: Option<std::time::SystemTime>,
}

#[derive(Debug, Clone, Copy)]
enum CookieExpiration {
    Delete,
    Keep(Option<std::time::SystemTime>),
}

fn parse_cookie_name_value(first: Option<&str>) -> Option<(&str, &str)> {
    let first = first?;
    let (name, val) = first.split_once('=')?;
    let name = name.trim();
    if name.is_empty() {
        return None;
    }
    Some((name, val.trim()))
}

fn parse_set_cookie_attrs<'a>(parts: impl Iterator<Item = &'a str>) -> SetCookieAttrs {
    let mut attrs = SetCookieAttrs::default();
    for raw in parts {
        let raw = raw.trim();
        if raw.is_empty() {
            continue;
        }
        if let Some((k, v)) = raw.split_once('=') {
            let k = k.trim().to_ascii_lowercase();
            let v = v.trim();
            match k.as_str() {
                "domain" => {
                    let mut d = v.trim_matches('"').trim().to_ascii_lowercase();
                    if let Some(stripped) = d.strip_prefix('.') {
                        d = stripped.to_string();
                    }
                    if !d.is_empty() {
                        attrs.domain = Some(d);
                    }
                }
                "path" => {
                    let p = v.trim_matches('"').trim();
                    if p.starts_with('/') {
                        attrs.path = Some(p.to_string());
                    }
                }
                "max-age" => {
                    if let Ok(n) = v.parse::<i64>() {
                        attrs.max_age = Some(n);
                    }
                }
                "samesite" => {
                    let ss = v.trim_matches('"').trim();
                    attrs.same_site = match ss.to_ascii_lowercase().as_str() {
                        "lax" => Some(CookieSameSite::Lax),
                        "strict" => Some(CookieSameSite::Strict),
                        "none" => Some(CookieSameSite::None),
                        _ => None,
                    };
                }
                "expires" => {
                    if let Some(t) = parse_http_date(v) {
                        attrs.expires_at = Some(t);
                    }
                }
                _ => {}
            }
        } else {
            match raw.to_ascii_lowercase().as_str() {
                "secure" => attrs.secure = true,
                "httponly" => attrs.http_only = true,
                _ => {}
            }
        }
    }
    attrs
}

fn cookie_domain_for_set_cookie(
    host: Option<&str>,
    domain_attr: Option<String>,
) -> Option<CookieDomain> {
    match domain_attr {
        Some(d) => {
            let h = host?;
            let domain = CookieDomain::Domain(d);
            if domain_matches(&domain, Some(h)) {
                Some(domain)
            } else {
                None
            }
        }
        None => {
            let h = host?;
            Some(CookieDomain::HostOnly(h.to_string()))
        }
    }
}

fn compute_cookie_expiration(
    max_age: Option<i64>,
    mut expires_at: Option<std::time::SystemTime>,
) -> CookieExpiration {
    let now = std::time::SystemTime::now();
    if let Some(n) = max_age {
        if n <= 0 {
            return CookieExpiration::Delete;
        }
        let Ok(secs) = u64::try_from(n) else {
            return CookieExpiration::Delete;
        };
        expires_at = now.checked_add(std::time::Duration::from_secs(secs));
    }
    if let Some(exp) = expires_at {
        if exp <= now {
            return CookieExpiration::Delete;
        }
    }
    CookieExpiration::Keep(expires_at)
}

fn request_host(request: &Request) -> Option<String> {
    let host = request.headers().get("host")?;
    let s = std::str::from_utf8(host).ok()?;
    let host = s.trim();
    if host.is_empty() {
        return None;
    }
    // Strip port if present.
    Some(host.split(':').next().unwrap_or(host).to_ascii_lowercase())
}

fn request_is_secure(request: &Request) -> bool {
    if let Some(info) = request.get_extension::<crate::request::ConnectionInfo>() {
        if info.is_tls {
            return true;
        }
    }

    if let Some(forwarded) = request.headers().get("forwarded") {
        if let Ok(s) = std::str::from_utf8(forwarded) {
            for entry in s.split(',') {
                for param in entry.split(';') {
                    let param = param.trim();
                    if let Some((k, v)) = param.split_once('=') {
                        if k.trim().eq_ignore_ascii_case("proto") {
                            let proto = v.trim().trim_matches('"');
                            if proto.eq_ignore_ascii_case("https") {
                                return true;
                            }
                        }
                    }
                }
            }
        }
    }

    if let Some(proto) = request.headers().get("x-forwarded-proto") {
        let first = proto.split(|&b| b == b',').next().unwrap_or(proto);
        let first = trim_ascii_bytes(first);
        return first.eq_ignore_ascii_case(b"https");
    }
    if let Some(ssl) = request.headers().get("x-forwarded-ssl") {
        return ssl.eq_ignore_ascii_case(b"on");
    }
    if let Some(https) = request.headers().get("front-end-https") {
        return https.eq_ignore_ascii_case(b"on");
    }

    false
}

fn trim_ascii_bytes(mut bytes: &[u8]) -> &[u8] {
    while matches!(bytes.first(), Some(b' ' | b'\t')) {
        bytes = &bytes[1..];
    }
    while matches!(bytes.last(), Some(b' ' | b'\t')) {
        bytes = &bytes[..bytes.len() - 1];
    }
    bytes
}

fn default_cookie_path(request_path: &str) -> String {
    // RFC 6265 default-path algorithm (5.1.4).
    if !request_path.starts_with('/') {
        return "/".to_string();
    }
    if request_path == "/" {
        return "/".to_string();
    }
    match request_path.rfind('/') {
        Some(0) | None => "/".to_string(),
        Some(idx) => request_path[..idx].to_string(),
    }
}

fn domain_matches(domain: &CookieDomain, host: Option<&str>) -> bool {
    match domain {
        CookieDomain::Any => true,
        CookieDomain::HostOnly(d) => host.is_some_and(|h| h.eq_ignore_ascii_case(d)),
        CookieDomain::Domain(d) => {
            let Some(h) = host else { return false };
            if h.eq_ignore_ascii_case(d) {
                return true;
            }
            // Suffix match with dot boundary.
            h.len() > d.len() && h.ends_with(d) && h.as_bytes()[h.len() - d.len() - 1] == b'.'
        }
    }
}

fn path_matches(cookie_path: &str, request_path: &str) -> bool {
    if cookie_path == "/" {
        return request_path.starts_with('/');
    }
    if !request_path.starts_with(cookie_path) {
        return false;
    }
    if cookie_path.ends_with('/') {
        return true;
    }
    request_path
        .as_bytes()
        .get(cookie_path.len())
        .is_none_or(|&b| b == b'/')
}

fn parse_http_date(input: &str) -> Option<std::time::SystemTime> {
    // Parse IMF-fixdate: "Wed, 21 Oct 2015 07:28:00 GMT"
    // We intentionally keep this minimal; invalid dates are ignored per RFC6265.
    let s = input.trim().trim_matches('"').trim();
    let (_dow, rest) = s.split_once(',')?;
    let rest = rest.trim();
    let mut it = rest.split_whitespace();
    let day = it.next()?.parse::<u32>().ok()?;
    let month = match it.next()? {
        "Jan" => 1,
        "Feb" => 2,
        "Mar" => 3,
        "Apr" => 4,
        "May" => 5,
        "Jun" => 6,
        "Jul" => 7,
        "Aug" => 8,
        "Sep" => 9,
        "Oct" => 10,
        "Nov" => 11,
        "Dec" => 12,
        _ => return None,
    };
    let year = it.next()?.parse::<i32>().ok()?;
    let time = it.next()?;
    let tz = it.next()?;
    if tz != "GMT" {
        return None;
    }
    let (hh, mm, ss) = {
        let mut t = time.split(':');
        let hh = t.next()?.parse::<u32>().ok()?;
        let mm = t.next()?.parse::<u32>().ok()?;
        let ss = t.next()?.parse::<u32>().ok()?;
        (hh, mm, ss)
    };

    // Convert to unix timestamp using a small civil->days function.
    fn days_from_civil(y: i32, m: u32, d: u32) -> i64 {
        // Howard Hinnant's algorithm.
        let y = i64::from(y) - i64::from(m <= 2);
        let era = (if y >= 0 { y } else { y - 399 }) / 400;
        let yoe = y - era * 400;
        let m = i64::from(m);
        let doy = (153 * (m + if m > 2 { -3 } else { 9 }) + 2) / 5 + i64::from(d) - 1;
        let doe = yoe * 365 + yoe / 4 - yoe / 100 + doy;
        era * 146097 + doe - 719468
    }

    let days = days_from_civil(year, month, day);
    let secs = days
        .checked_mul(86_400)?
        .checked_add(i64::from(hh) * 3600 + i64::from(mm) * 60 + i64::from(ss))?;
    if secs < 0 {
        return None;
    }
    let secs_u64 = u64::try_from(secs).ok()?;
    Some(std::time::UNIX_EPOCH + std::time::Duration::from_secs(secs_u64))
}

/// Test client for in-process HTTP testing.
///
/// `TestClient` wraps a handler and provides an HTTP-like interface
/// for testing without network overhead. It maintains a cookie jar
/// for session persistence across requests.
///
/// # Thread Safety
///
/// `TestClient` is thread-safe and can be shared across test threads.
/// The internal cookie jar is protected by a mutex.
///
/// # Example
///
/// ```ignore
/// let client = TestClient::new(my_handler);
///
/// // Simple GET request
/// let response = client.get("/users").send();
/// assert_eq!(response.status(), StatusCode::OK);
///
/// // POST with JSON body
/// let response = client
///     .post("/users")
///     .json(&CreateUser { name: "Alice" })
///     .send();
/// assert_eq!(response.status(), StatusCode::CREATED);
///
/// // Request with headers
/// let response = client
///     .get("/protected")
///     .header("Authorization", "Bearer token123")
///     .send();
/// ```
pub struct TestClient<H> {
    handler: Arc<H>,
    cookies: Arc<Mutex<CookieJar>>,
    dependency_overrides: Arc<DependencyOverrides>,
    seed: Option<u64>,
    request_id_counter: Arc<std::sync::atomic::AtomicU64>,
}

impl<H: Handler + 'static> TestClient<H> {
    /// Creates a new test client wrapping the given handler.
    ///
    /// # Example
    ///
    /// ```ignore
    /// let client = TestClient::new(my_handler);
    /// ```
    pub fn new(handler: H) -> Self {
        let dependency_overrides = handler
            .dependency_overrides()
            .unwrap_or_else(|| Arc::new(DependencyOverrides::new()));
        Self {
            handler: Arc::new(handler),
            cookies: Arc::new(Mutex::new(CookieJar::new())),
            dependency_overrides,
            seed: None,
            request_id_counter: Arc::new(std::sync::atomic::AtomicU64::new(1)),
        }
    }

    /// Creates a test client with a deterministic seed for the Lab runtime.
    ///
    /// Using the same seed produces identical execution order for
    /// concurrent operations, enabling reproducible test failures.
    ///
    /// # Example
    ///
    /// ```ignore
    /// let client = TestClient::with_seed(my_handler, 42);
    /// ```
    pub fn with_seed(handler: H, seed: u64) -> Self {
        let dependency_overrides = handler
            .dependency_overrides()
            .unwrap_or_else(|| Arc::new(DependencyOverrides::new()));
        Self {
            handler: Arc::new(handler),
            cookies: Arc::new(Mutex::new(CookieJar::new())),
            dependency_overrides,
            seed: Some(seed),
            request_id_counter: Arc::new(std::sync::atomic::AtomicU64::new(1)),
        }
    }

    /// Returns the seed used for deterministic testing, if set.
    #[must_use]
    pub fn seed(&self) -> Option<u64> {
        self.seed
    }

    /// Returns a reference to the cookie jar.
    ///
    /// Note: The jar is protected by a mutex, so concurrent access
    /// is safe but may block.
    pub fn cookies(&self) -> parking_lot::MutexGuard<'_, CookieJar> {
        self.cookies.lock()
    }

    /// Clears all cookies from the jar.
    pub fn clear_cookies(&self) {
        self.cookies().clear();
    }

    /// Creates a GET request builder.
    #[must_use]
    pub fn get(&self, path: &str) -> RequestBuilder<'_, H> {
        RequestBuilder::new(self, Method::Get, path)
    }

    /// Creates a POST request builder.
    #[must_use]
    pub fn post(&self, path: &str) -> RequestBuilder<'_, H> {
        RequestBuilder::new(self, Method::Post, path)
    }

    /// Creates a PUT request builder.
    #[must_use]
    pub fn put(&self, path: &str) -> RequestBuilder<'_, H> {
        RequestBuilder::new(self, Method::Put, path)
    }

    /// Creates a DELETE request builder.
    #[must_use]
    pub fn delete(&self, path: &str) -> RequestBuilder<'_, H> {
        RequestBuilder::new(self, Method::Delete, path)
    }

    /// Creates a PATCH request builder.
    #[must_use]
    pub fn patch(&self, path: &str) -> RequestBuilder<'_, H> {
        RequestBuilder::new(self, Method::Patch, path)
    }

    /// Creates an OPTIONS request builder.
    #[must_use]
    pub fn options(&self, path: &str) -> RequestBuilder<'_, H> {
        RequestBuilder::new(self, Method::Options, path)
    }

    /// Creates a HEAD request builder.
    #[must_use]
    pub fn head(&self, path: &str) -> RequestBuilder<'_, H> {
        RequestBuilder::new(self, Method::Head, path)
    }

    /// Creates a request builder with a custom method.
    #[must_use]
    pub fn request(&self, method: Method, path: &str) -> RequestBuilder<'_, H> {
        RequestBuilder::new(self, method, path)
    }

    /// Register a dependency override for this test client.
    pub fn override_dependency<T, F, Fut>(&self, f: F)
    where
        T: FromDependency,
        F: Fn(&RequestContext, &mut Request) -> Fut + Send + Sync + 'static,
        Fut: Future<Output = Result<T, T::Error>> + Send + 'static,
    {
        self.dependency_overrides.insert::<T, F, Fut>(f);
    }

    /// Register a fixed dependency override value.
    pub fn override_dependency_value<T>(&self, value: T)
    where
        T: FromDependency,
    {
        self.dependency_overrides.insert_value(value);
    }

    /// Clear all registered dependency overrides.
    pub fn clear_dependency_overrides(&self) {
        self.dependency_overrides.clear();
    }

    /// Generates a unique request ID for tracing.
    fn next_request_id(&self) -> u64 {
        self.request_id_counter
            .fetch_add(1, std::sync::atomic::Ordering::SeqCst)
    }

    /// Executes a request and returns the response.
    ///
    /// This is called internally by `RequestBuilder::send()`.
    fn execute(&self, mut request: Request) -> TestResponse {
        // Many features (cookies, redirects, absolute URL building) require a host.
        // In tests, default to a stable host if one wasn't provided.
        if !request.headers().contains("host") {
            request.headers_mut().insert("host", b"testserver".to_vec());
        }

        // Add cookies from jar to request
        {
            let jar = self.cookies();
            if let Some(cookie_header) = jar.cookie_header_for_request(&request) {
                request
                    .headers_mut()
                    .insert("cookie", cookie_header.into_bytes());
            }
        }

        // Create test context with Cx::for_testing()
        let cx = Cx::for_testing();
        let request_id = self.next_request_id();
        let ctx =
            RequestContext::with_overrides(cx, request_id, Arc::clone(&self.dependency_overrides));

        // The TestClient API is synchronous; run the async handler to completion.
        let response = futures_executor::block_on(self.handler.call(&ctx, &mut request));

        // Extract cookies from response
        {
            let mut jar = self.cookies();
            for (name, value) in response.headers() {
                if name.eq_ignore_ascii_case("set-cookie") {
                    jar.parse_set_cookie(&request, value);
                }
            }
        }

        TestResponse::new(response, request_id)
    }
}

impl<H> Clone for TestClient<H> {
    fn clone(&self) -> Self {
        Self {
            handler: Arc::clone(&self.handler),
            cookies: Arc::clone(&self.cookies),
            dependency_overrides: Arc::clone(&self.dependency_overrides),
            seed: self.seed,
            request_id_counter: Arc::clone(&self.request_id_counter),
        }
    }
}

/// Builder for constructing test requests with a fluent API.
///
/// Use the methods on [`TestClient`] to create a request builder,
/// then chain configuration methods and call [`send`](Self::send) to execute.
///
/// # Example
///
/// ```ignore
/// let response = client
///     .post("/api/items")
///     .header("Content-Type", "application/json")
///     .body(r#"{"name": "Widget"}"#)
///     .send();
/// ```
pub struct RequestBuilder<'a, H> {
    client: &'a TestClient<H>,
    method: Method,
    path: String,
    query: Option<String>,
    headers: Vec<(String, Vec<u8>)>,
    body: Body,
}

impl<'a, H: Handler + 'static> RequestBuilder<'a, H> {
    /// Creates a new request builder.
    fn new(client: &'a TestClient<H>, method: Method, path: &str) -> Self {
        // Split path and query string
        let (path, query) = if let Some(idx) = path.find('?') {
            (path[..idx].to_string(), Some(path[idx + 1..].to_string()))
        } else {
            (path.to_string(), None)
        };

        Self {
            client,
            method,
            path,
            query,
            headers: Vec::new(),
            body: Body::Empty,
        }
    }

    /// Sets a query string parameter.
    ///
    /// Multiple calls append parameters.
    ///
    /// # Example
    ///
    /// ```ignore
    /// client.get("/search").query("q", "rust").query("limit", "10").send()
    /// ```
    #[must_use]
    pub fn query(mut self, key: &str, value: &str) -> Self {
        let param = format!("{key}={value}");
        self.query = Some(match self.query {
            Some(q) => format!("{q}&{param}"),
            None => param,
        });
        self
    }

    /// Sets a request header.
    ///
    /// # Example
    ///
    /// ```ignore
    /// client.get("/api").header("Authorization", "Bearer token").send()
    /// ```
    #[must_use]
    pub fn header(mut self, name: impl Into<String>, value: impl Into<Vec<u8>>) -> Self {
        self.headers.push((name.into(), value.into()));
        self
    }

    /// Sets a request header with a string value.
    #[must_use]
    pub fn header_str(self, name: impl Into<String>, value: &str) -> Self {
        self.header(name, value.as_bytes().to_vec())
    }

    /// Sets the request body as raw bytes.
    ///
    /// # Example
    ///
    /// ```ignore
    /// client.post("/upload").body(b"binary data".to_vec()).send()
    /// ```
    #[must_use]
    pub fn body(mut self, body: impl Into<Vec<u8>>) -> Self {
        self.body = Body::Bytes(body.into());
        self
    }

    /// Sets the request body as a string.
    #[must_use]
    pub fn body_str(self, body: &str) -> Self {
        self.body(body.as_bytes().to_vec())
    }

    /// Sets the request body as JSON.
    ///
    /// Automatically sets the Content-Type header to `application/json`.
    ///
    /// # Example
    ///
    /// ```ignore
    /// #[derive(Serialize)]
    /// struct CreateUser { name: String }
    ///
    /// client.post("/users").json(&CreateUser { name: "Alice".into() }).send()
    /// ```
    #[must_use]
    pub fn json<T: serde::Serialize>(mut self, value: &T) -> Self {
        let bytes = serde_json::to_vec(value).expect("JSON serialization failed");
        self.body = Body::Bytes(bytes);
        self.headers
            .push(("content-type".to_string(), b"application/json".to_vec()));
        self
    }

    /// Sets a cookie for this request only.
    ///
    /// This does not affect the client's cookie jar.
    #[must_use]
    pub fn cookie(self, name: &str, value: &str) -> Self {
        let cookie = format!("{name}={value}");
        self.header("cookie", cookie.into_bytes())
    }

    /// Sends the request and returns the response.
    ///
    /// # Example
    ///
    /// ```ignore
    /// let response = client.get("/").send();
    /// ```
    #[must_use]
    pub fn send(self) -> TestResponse {
        let mut request = Request::new(self.method, self.path);
        request.set_query(self.query);
        request.set_body(self.body);

        for (name, value) in self.headers {
            request.headers_mut().insert(name, value);
        }

        self.client.execute(request)
    }
}

/// Response from a test request with assertion helpers.
///
/// `TestResponse` wraps a [`Response`] and provides convenient methods
/// for accessing response data and making assertions in tests.
///
/// # Example
///
/// ```ignore
/// let response = client.get("/api/user").send();
///
/// assert_eq!(response.status(), StatusCode::OK);
/// assert!(response.header("content-type").contains("application/json"));
///
/// let user: User = response.json().unwrap();
/// assert_eq!(user.name, "Alice");
/// ```
#[derive(Debug)]
pub struct TestResponse {
    inner: Response,
    request_id: u64,
}

impl TestResponse {
    /// Creates a new test response.
    fn new(response: Response, request_id: u64) -> Self {
        Self {
            inner: response,
            request_id,
        }
    }

    /// Returns the request ID for tracing.
    #[must_use]
    pub fn request_id(&self) -> u64 {
        self.request_id
    }

    /// Returns the HTTP status code.
    #[must_use]
    pub fn status(&self) -> StatusCode {
        self.inner.status()
    }

    /// Returns the status code as a u16.
    #[must_use]
    pub fn status_code(&self) -> u16 {
        self.inner.status().as_u16()
    }

    /// Checks if the status is successful (2xx).
    #[must_use]
    pub fn is_success(&self) -> bool {
        let code = self.status_code();
        (200..300).contains(&code)
    }

    /// Checks if the status is a redirect (3xx).
    #[must_use]
    pub fn is_redirect(&self) -> bool {
        let code = self.status_code();
        (300..400).contains(&code)
    }

    /// Checks if the status is a client error (4xx).
    #[must_use]
    pub fn is_client_error(&self) -> bool {
        let code = self.status_code();
        (400..500).contains(&code)
    }

    /// Checks if the status is a server error (5xx).
    #[must_use]
    pub fn is_server_error(&self) -> bool {
        let code = self.status_code();
        (500..600).contains(&code)
    }

    /// Returns all headers.
    #[must_use]
    pub fn headers(&self) -> &[(String, Vec<u8>)] {
        self.inner.headers()
    }

    /// Returns a header value by name (case-insensitive).
    #[must_use]
    pub fn header(&self, name: &str) -> Option<&[u8]> {
        let name_lower = name.to_ascii_lowercase();
        self.inner
            .headers()
            .iter()
            .find(|(n, _)| n.to_ascii_lowercase() == name_lower)
            .map(|(_, v)| v.as_slice())
    }

    /// Returns a header value as a string (case-insensitive).
    #[must_use]
    pub fn header_str(&self, name: &str) -> Option<&str> {
        self.header(name).and_then(|v| std::str::from_utf8(v).ok())
    }

    /// Returns the Content-Type header value.
    #[must_use]
    pub fn content_type(&self) -> Option<&str> {
        self.header_str("content-type")
    }

    /// Returns the body as raw bytes.
    #[must_use]
    pub fn bytes(&self) -> &[u8] {
        match self.inner.body_ref() {
            ResponseBody::Empty => &[],
            ResponseBody::Bytes(b) => b,
            ResponseBody::Stream(_) => {
                panic!("streaming response body not supported in TestResponse")
            }
        }
    }

    /// Returns the body as a UTF-8 string.
    ///
    /// # Panics
    ///
    /// Panics if the body is not valid UTF-8.
    #[must_use]
    pub fn text(&self) -> &str {
        std::str::from_utf8(self.bytes()).expect("response body is not valid UTF-8")
    }

    /// Tries to return the body as a UTF-8 string.
    #[must_use]
    pub fn text_opt(&self) -> Option<&str> {
        std::str::from_utf8(self.bytes()).ok()
    }

    /// Parses the body as JSON.
    ///
    /// # Errors
    ///
    /// Returns an error if the body cannot be parsed as the target type.
    ///
    /// # Example
    ///
    /// ```ignore
    /// #[derive(Deserialize)]
    /// struct User { name: String }
    ///
    /// let user: User = response.json().unwrap();
    /// ```
    pub fn json<T: serde::de::DeserializeOwned>(&self) -> Result<T, serde_json::Error> {
        serde_json::from_slice(self.bytes())
    }

    /// Returns the body length.
    #[must_use]
    pub fn content_length(&self) -> usize {
        self.bytes().len()
    }

    /// Returns the underlying response.
    #[must_use]
    pub fn into_inner(self) -> Response {
        self.inner
    }

    // =========================================================================
    // Assertion Helpers
    // =========================================================================

    /// Asserts that the status code equals the expected value.
    ///
    /// # Panics
    ///
    /// Panics with a descriptive message if the assertion fails.
    #[must_use]
    pub fn assert_status(&self, expected: StatusCode) -> &Self {
        assert_eq!(
            self.status(),
            expected,
            "Expected status {}, got {} for request {}",
            expected.as_u16(),
            self.status_code(),
            self.request_id
        );
        self
    }

    /// Asserts that the status code equals the expected u16 value.
    ///
    /// # Panics
    ///
    /// Panics with a descriptive message if the assertion fails.
    #[must_use]
    pub fn assert_status_code(&self, expected: u16) -> &Self {
        assert_eq!(
            self.status_code(),
            expected,
            "Expected status {expected}, got {} for request {}",
            self.status_code(),
            self.request_id
        );
        self
    }

    /// Asserts that the response is successful (2xx).
    ///
    /// # Panics
    ///
    /// Panics if the status is not in the 2xx range.
    #[must_use]
    pub fn assert_success(&self) -> &Self {
        assert!(
            self.is_success(),
            "Expected success status, got {} for request {}",
            self.status_code(),
            self.request_id
        );
        self
    }

    /// Asserts that a header exists with the given value.
    ///
    /// # Panics
    ///
    /// Panics if the header doesn't exist or doesn't match.
    #[must_use]
    pub fn assert_header(&self, name: &str, expected: &str) -> &Self {
        let actual = self.header_str(name);
        assert_eq!(
            actual,
            Some(expected),
            "Expected header '{name}' to be '{expected}', got {:?} for request {}",
            actual,
            self.request_id
        );
        self
    }

    /// Asserts that the body equals the expected string.
    ///
    /// # Panics
    ///
    /// Panics if the body doesn't match.
    #[must_use]
    pub fn assert_text(&self, expected: &str) -> &Self {
        assert_eq!(
            self.text(),
            expected,
            "Body mismatch for request {}",
            self.request_id
        );
        self
    }

    /// Asserts that the body contains the expected substring.
    ///
    /// # Panics
    ///
    /// Panics if the body doesn't contain the substring.
    #[must_use]
    pub fn assert_text_contains(&self, expected: &str) -> &Self {
        assert!(
            self.text().contains(expected),
            "Expected body to contain '{}', got '{}' for request {}",
            expected,
            self.text(),
            self.request_id
        );
        self
    }

    /// Asserts that the JSON body equals the expected value.
    ///
    /// # Panics
    ///
    /// Panics if parsing fails or the value doesn't match.
    #[must_use]
    pub fn assert_json<T>(&self, expected: &T) -> &Self
    where
        T: serde::de::DeserializeOwned + serde::Serialize + PartialEq + std::fmt::Debug,
    {
        let actual: T = self.json().expect("Failed to parse response as JSON");
        assert_eq!(
            actual, *expected,
            "JSON body mismatch for request {}",
            self.request_id
        );
        self
    }

    /// Asserts that the JSON body contains all fields from the expected value.
    ///
    /// This performs partial matching: the actual response may contain additional
    /// fields not present in `expected`, but all fields in `expected` must be
    /// present in the actual response with matching values.
    ///
    /// # Panics
    ///
    /// Panics if parsing fails or partial matching fails.
    ///
    /// # Example
    ///
    /// ```ignore
    /// // Response body: {"id": 1, "name": "Alice", "email": "alice@example.com"}
    /// // This passes because all expected fields match:
    /// response.assert_json_contains(&json!({"name": "Alice"}));
    /// ```
    #[must_use]
    pub fn assert_json_contains(&self, expected: &serde_json::Value) -> &Self {
        let actual: serde_json::Value = self.json().expect("Failed to parse response as JSON");
        if let Err(path) = json_contains(&actual, expected) {
            panic!(
                "JSON partial match failed at path '{}' for request {}\n\
                 Expected (partial):\n{}\n\
                 Actual:\n{}",
                path,
                self.request_id,
                serde_json::to_string_pretty(expected).unwrap_or_else(|_| format!("{expected:?}")),
                serde_json::to_string_pretty(&actual).unwrap_or_else(|_| format!("{actual:?}")),
            );
        }
        self
    }

    /// Asserts that the body matches the given regex pattern.
    ///
    /// # Panics
    ///
    /// Panics if the pattern doesn't match or is invalid.
    ///
    /// # Example
    ///
    /// ```ignore
    /// response.assert_body_matches(r"user_\d+");
    /// ```
    #[cfg(feature = "regex")]
    #[must_use]
    pub fn assert_body_matches(&self, pattern: &str) -> &Self {
        let re = regex::Regex::new(pattern)
            .unwrap_or_else(|e| panic!("Invalid regex pattern '{pattern}': {e}"));
        let body = self.text();
        assert!(
            re.is_match(body),
            "Expected body to match pattern '{}', got '{}' for request {}",
            pattern,
            body,
            self.request_id
        );
        self
    }

    /// Asserts that a header exists and matches the given regex pattern.
    ///
    /// # Panics
    ///
    /// Panics if the header doesn't exist, can't be read as UTF-8,
    /// or doesn't match the pattern.
    #[cfg(feature = "regex")]
    #[must_use]
    pub fn assert_header_matches(&self, name: &str, pattern: &str) -> &Self {
        let re = regex::Regex::new(pattern)
            .unwrap_or_else(|e| panic!("Invalid regex pattern '{pattern}': {e}"));
        let value = self
            .header_str(name)
            .unwrap_or_else(|| panic!("Header '{name}' not found for request {}", self.request_id));
        assert!(
            re.is_match(value),
            "Expected header '{}' to match pattern '{}', got '{}' for request {}",
            name,
            pattern,
            value,
            self.request_id
        );
        self
    }

    /// Asserts that a header exists (regardless of value).
    ///
    /// # Panics
    ///
    /// Panics if the header doesn't exist.
    #[must_use]
    pub fn assert_header_exists(&self, name: &str) -> &Self {
        assert!(
            self.header(name).is_some(),
            "Expected header '{}' to exist for request {}",
            name,
            self.request_id
        );
        self
    }

    /// Asserts that a header does not exist.
    ///
    /// # Panics
    ///
    /// Panics if the header exists.
    #[must_use]
    pub fn assert_header_missing(&self, name: &str) -> &Self {
        assert!(
            self.header(name).is_none(),
            "Expected header '{}' to not exist for request {}, but found {:?}",
            name,
            self.request_id,
            self.header_str(name)
        );
        self
    }

    /// Asserts that the Content-Type header contains the expected value.
    ///
    /// This is a convenience method that checks if the Content-Type header
    /// contains the given string (useful for checking media types ignoring charset).
    ///
    /// # Panics
    ///
    /// Panics if the Content-Type header doesn't exist or doesn't contain the expected value.
    #[must_use]
    pub fn assert_content_type_contains(&self, expected: &str) -> &Self {
        let ct = self.content_type().unwrap_or_else(|| {
            panic!(
                "Content-Type header not found for request {}",
                self.request_id
            )
        });
        assert!(
            ct.contains(expected),
            "Expected Content-Type to contain '{}', got '{}' for request {}",
            expected,
            ct,
            self.request_id
        );
        self
    }
}

// =============================================================================
// Partial JSON Matching
// =============================================================================

/// Checks if `actual` contains all fields from `expected`.
///
/// Returns `Ok(())` if matching succeeds, or `Err(path)` where `path` is
/// the JSON path to the first mismatch.
///
/// # Matching Rules
///
/// - **Objects**: All keys in `expected` must exist in `actual` with matching values.
///   Extra keys in `actual` are ignored.
/// - **Arrays**: Must match exactly (same length, same elements in order).
/// - **Primitives**: Must be equal.
///
/// # Example
///
/// ```
/// use fastapi_core::testing::json_contains;
/// use serde_json::json;
///
/// // Partial match succeeds - actual has extra "email" field
/// let actual = json!({"id": 1, "name": "Alice", "email": "alice@example.com"});
/// let expected = json!({"name": "Alice"});
/// assert!(json_contains(&actual, &expected).is_ok());
///
/// // Mismatch fails
/// let expected = json!({"name": "Bob"});
/// assert!(json_contains(&actual, &expected).is_err());
/// ```
pub fn json_contains(
    actual: &serde_json::Value,
    expected: &serde_json::Value,
) -> Result<(), String> {
    json_contains_at_path(actual, expected, "$")
}

fn json_contains_at_path(
    actual: &serde_json::Value,
    expected: &serde_json::Value,
    path: &str,
) -> Result<(), String> {
    use serde_json::Value;

    match (actual, expected) {
        // For objects, check that all expected keys exist with matching values
        (Value::Object(actual_obj), Value::Object(expected_obj)) => {
            for (key, expected_val) in expected_obj {
                let child_path = format!("{path}.{key}");
                match actual_obj.get(key) {
                    Some(actual_val) => {
                        json_contains_at_path(actual_val, expected_val, &child_path)?;
                    }
                    None => {
                        return Err(child_path);
                    }
                }
            }
            Ok(())
        }
        // For arrays, require exact match (partial array matching is ambiguous)
        (Value::Array(actual_arr), Value::Array(expected_arr)) => {
            if actual_arr.len() != expected_arr.len() {
                return Err(format!("{path}[length]"));
            }
            for (i, (actual_elem, expected_elem)) in
                actual_arr.iter().zip(expected_arr.iter()).enumerate()
            {
                let child_path = format!("{path}[{i}]");
                json_contains_at_path(actual_elem, expected_elem, &child_path)?;
            }
            Ok(())
        }
        // For primitives, require exact match
        _ => {
            if actual == expected {
                Ok(())
            } else {
                Err(path.to_string())
            }
        }
    }
}

// =============================================================================
// Helper Traits for Assertion Macros
// =============================================================================

/// Helper trait to convert various types to u16 for status code comparison.
///
/// This enables the `assert_status!` macro to accept both `u16` literals
/// and `StatusCode` values.
pub trait IntoStatusU16 {
    fn into_status_u16(self) -> u16;
}

impl IntoStatusU16 for u16 {
    fn into_status_u16(self) -> u16 {
        self
    }
}

impl IntoStatusU16 for StatusCode {
    fn into_status_u16(self) -> u16 {
        self.as_u16()
    }
}

// Also implement for i32 since integer literals without suffix default to i32
impl IntoStatusU16 for i32 {
    #[allow(clippy::cast_possible_truncation, clippy::cast_sign_loss)]
    fn into_status_u16(self) -> u16 {
        // This is intentional - HTTP status codes are always 3-digit positive numbers
        self as u16
    }
}

// =============================================================================
// Assertion Macros
// =============================================================================

/// Asserts that a test response has the expected HTTP status code.
///
/// Accepts either a `u16` literal or a `StatusCode` value.
///
/// # Examples
///
/// ```ignore
/// use fastapi_core::assert_status;
///
/// let response = client.get("/users").send();
/// assert_status!(response, 200);
/// assert_status!(response, StatusCode::OK);
/// ```
///
/// With custom message:
/// ```ignore
/// assert_status!(response, 404, "User should not be found");
/// ```
#[macro_export]
macro_rules! assert_status {
    ($response:expr, $expected:expr) => {{
        let response = &$response;
        let actual = response.status_code();
        // Use a trait to handle both u16 and StatusCode
        let expected_code: u16 = $crate::testing::IntoStatusU16::into_status_u16($expected);
        if actual != expected_code {
            panic!(
                "assertion failed: `(response.status() == {})`\n\
                 expected status: {}\n\
                 actual status: {}\n\
                 request id: {}\n\
                 response body: {}",
                expected_code,
                expected_code,
                actual,
                response.request_id(),
                response.text_opt().unwrap_or("<non-UTF8 body>")
            );
        }
    }};
    ($response:expr, $expected:expr, $($msg:tt)+) => {{
        let response = &$response;
        let actual = response.status_code();
        let expected_code: u16 = $crate::testing::IntoStatusU16::into_status_u16($expected);
        if actual != expected_code {
            panic!(
                "{}\n\
                 assertion failed: `(response.status() == {})`\n\
                 expected status: {}\n\
                 actual status: {}\n\
                 request id: {}\n\
                 response body: {}",
                format_args!($($msg)+),
                expected_code,
                expected_code,
                actual,
                response.request_id(),
                response.text_opt().unwrap_or("<non-UTF8 body>")
            );
        }
    }};
}

/// Asserts that a test response has a header with the expected value.
///
/// # Examples
///
/// ```ignore
/// use fastapi_core::assert_header;
///
/// let response = client.get("/api").send();
/// assert_header!(response, "Content-Type", "application/json");
/// ```
///
/// With custom message:
/// ```ignore
/// assert_header!(response, "X-Custom", "value", "Custom header should be set");
/// ```
#[macro_export]
macro_rules! assert_header {
    ($response:expr, $name:expr, $expected:expr) => {{
        let response = &$response;
        let name = $name;
        let expected = $expected;
        let actual = response.header_str(name);
        if actual != Some(expected) {
            panic!(
                "assertion failed: `(response.header(\"{}\") == \"{}\")`\n\
                 expected header '{}': \"{}\"\n\
                 actual header '{}': {:?}\n\
                 request id: {}",
                name,
                expected,
                name,
                expected,
                name,
                actual,
                response.request_id()
            );
        }
    }};
    ($response:expr, $name:expr, $expected:expr, $($msg:tt)+) => {{
        let response = &$response;
        let name = $name;
        let expected = $expected;
        let actual = response.header_str(name);
        if actual != Some(expected) {
            panic!(
                "{}\n\
                 assertion failed: `(response.header(\"{}\") == \"{}\")`\n\
                 expected header '{}': \"{}\"\n\
                 actual header '{}': {:?}\n\
                 request id: {}",
                format_args!($($msg)+),
                name,
                expected,
                name,
                expected,
                name,
                actual,
                response.request_id()
            );
        }
    }};
}

/// Asserts that a test response body contains the expected substring.
///
/// # Examples
///
/// ```ignore
/// use fastapi_core::assert_body_contains;
///
/// let response = client.get("/hello").send();
/// assert_body_contains!(response, "Hello");
/// ```
///
/// With custom message:
/// ```ignore
/// assert_body_contains!(response, "error", "Response should contain error message");
/// ```
#[macro_export]
macro_rules! assert_body_contains {
    ($response:expr, $expected:expr) => {{
        let response = &$response;
        let expected = $expected;
        let body = response.text();
        if !body.contains(expected) {
            panic!(
                "assertion failed: response body does not contain \"{}\"\n\
                 expected substring: \"{}\"\n\
                 actual body: \"{}\"\n\
                 request id: {}",
                expected, expected, body, response.request_id()
            );
        }
    }};
    ($response:expr, $expected:expr, $($msg:tt)+) => {{
        let response = &$response;
        let expected = $expected;
        let body = response.text();
        if !body.contains(expected) {
            panic!(
                "{}\n\
                 assertion failed: response body does not contain \"{}\"\n\
                 expected substring: \"{}\"\n\
                 actual body: \"{}\"\n\
                 request id: {}",
                format_args!($($msg)+),
                expected,
                expected,
                body,
                response.request_id()
            );
        }
    }};
}

/// Asserts that a test response body matches the expected JSON value (partial match).
///
/// This macro performs partial JSON matching: the actual response may contain
/// additional fields not present in `expected`, but all fields in `expected`
/// must be present with matching values.
///
/// # Examples
///
/// ```ignore
/// use fastapi_core::assert_json;
/// use serde_json::json;
///
/// let response = client.get("/user/1").send();
/// // Response: {"id": 1, "name": "Alice", "email": "alice@example.com"}
///
/// // Exact match
/// assert_json!(response, {"id": 1, "name": "Alice", "email": "alice@example.com"});
///
/// // Partial match (ignores email field)
/// assert_json!(response, {"name": "Alice"});
/// ```
///
/// With custom message:
/// ```ignore
/// assert_json!(response, {"status": "ok"}, "API should return success status");
/// ```
#[macro_export]
macro_rules! assert_json {
    ($response:expr, $expected:tt) => {{
        let response = &$response;
        let expected = serde_json::json!($expected);
        let actual: serde_json::Value = response
            .json()
            .expect("Failed to parse response body as JSON");

        if let Err(path) = $crate::testing::json_contains(&actual, &expected) {
            panic!(
                "assertion failed: JSON partial match failed at path '{}'\n\
                 expected (partial):\n{}\n\
                 actual:\n{}\n\
                 request id: {}",
                path,
                serde_json::to_string_pretty(&expected).unwrap_or_else(|_| format!("{:?}", expected)),
                serde_json::to_string_pretty(&actual).unwrap_or_else(|_| format!("{:?}", actual)),
                response.request_id()
            );
        }
    }};
    ($response:expr, $expected:tt, $($msg:tt)+) => {{
        let response = &$response;
        let expected = serde_json::json!($expected);
        let actual: serde_json::Value = response
            .json()
            .expect("Failed to parse response body as JSON");

        if let Err(path) = $crate::testing::json_contains(&actual, &expected) {
            panic!(
                "{}\n\
                 assertion failed: JSON partial match failed at path '{}'\n\
                 expected (partial):\n{}\n\
                 actual:\n{}\n\
                 request id: {}",
                format_args!($($msg)+),
                path,
                serde_json::to_string_pretty(&expected).unwrap_or_else(|_| format!("{:?}", expected)),
                serde_json::to_string_pretty(&actual).unwrap_or_else(|_| format!("{:?}", actual)),
                response.request_id()
            );
        }
    }};
}

/// Asserts that a test response body matches the given regex pattern.
///
/// Requires the `regex` feature to be enabled.
///
/// # Examples
///
/// ```ignore
/// use fastapi_core::assert_body_matches;
///
/// let response = client.get("/user/1").send();
/// assert_body_matches!(response, r"user_\d+");
/// assert_body_matches!(response, r"^Hello.*World$");
/// ```
#[cfg(feature = "regex")]
#[macro_export]
macro_rules! assert_body_matches {
    ($response:expr, $pattern:expr) => {{
        let response = &$response;
        let pattern = $pattern;
        let re = regex::Regex::new(pattern)
            .unwrap_or_else(|e| panic!("Invalid regex pattern '{}': {}", pattern, e));
        let body = response.text();
        if !re.is_match(body) {
            panic!(
                "assertion failed: response body does not match pattern\n\
                 pattern: \"{}\"\n\
                 actual body: \"{}\"\n\
                 request id: {}",
                pattern, body, response.request_id()
            );
        }
    }};
    ($response:expr, $pattern:expr, $($msg:tt)+) => {{
        let response = &$response;
        let pattern = $pattern;
        let re = regex::Regex::new(pattern)
            .unwrap_or_else(|e| panic!("Invalid regex pattern '{}': {}", pattern, e));
        let body = response.text();
        if !re.is_match(body) {
            panic!(
                "{}\n\
                 assertion failed: response body does not match pattern\n\
                 pattern: \"{}\"\n\
                 actual body: \"{}\"\n\
                 request id: {}",
                format_args!($($msg)+),
                pattern,
                body,
                response.request_id()
            );
        }
    }};
}

// Note: json_contains is already public and accessible via crate::testing::json_contains

// ============================================================================
// Lab Runtime Testing Utilities
// ============================================================================

/// Configuration for Lab-based deterministic testing.
///
/// This configuration controls how the Lab runtime executes tests, including
/// virtual time, chaos injection, and deterministic scheduling.
///
/// # Example
///
/// ```ignore
/// use fastapi_core::testing::{LabTestConfig, LabTestClient};
///
/// // Basic deterministic test
/// let config = LabTestConfig::new(42);
/// let client = LabTestClient::with_config(my_handler, config);
///
/// // With chaos injection for stress testing
/// let config = LabTestConfig::new(42).with_light_chaos();
/// let client = LabTestClient::with_config(my_handler, config);
/// ```
#[derive(Debug, Clone)]
pub struct LabTestConfig {
    /// Seed for deterministic scheduling.
    pub seed: u64,
    /// Whether to enable chaos injection.
    pub chaos_enabled: bool,
    /// Chaos intensity (0.0 = none, 1.0 = max).
    pub chaos_intensity: f64,
    /// Maximum steps before timeout (prevents infinite loops).
    pub max_steps: Option<u64>,
    /// Whether to capture traces for debugging.
    pub capture_traces: bool,
}

impl Default for LabTestConfig {
    fn default() -> Self {
        Self {
            seed: 42,
            chaos_enabled: false,
            chaos_intensity: 0.0,
            max_steps: Some(10_000),
            capture_traces: false,
        }
    }
}

impl LabTestConfig {
    /// Creates a new Lab test configuration with the given seed.
    #[must_use]
    pub fn new(seed: u64) -> Self {
        Self {
            seed,
            ..Default::default()
        }
    }

    /// Enables light chaos injection (1% cancel, 5% delay).
    ///
    /// Suitable for CI pipelines - catches obvious bugs without excessive flakiness.
    #[must_use]
    pub fn with_light_chaos(mut self) -> Self {
        self.chaos_enabled = true;
        self.chaos_intensity = 0.05;
        self
    }

    /// Enables heavy chaos injection (10% cancel, 20% delay).
    ///
    /// Suitable for thorough stress testing before releases.
    #[must_use]
    pub fn with_heavy_chaos(mut self) -> Self {
        self.chaos_enabled = true;
        self.chaos_intensity = 0.2;
        self
    }

    /// Sets custom chaos intensity (0.0 to 1.0).
    #[must_use]
    pub fn with_chaos_intensity(mut self, intensity: f64) -> Self {
        self.chaos_enabled = intensity > 0.0;
        self.chaos_intensity = intensity.clamp(0.0, 1.0);
        self
    }

    /// Sets the maximum number of steps before timeout.
    #[must_use]
    pub fn with_max_steps(mut self, max: u64) -> Self {
        self.max_steps = Some(max);
        self
    }

    /// Disables the step limit (use with caution).
    #[must_use]
    pub fn without_step_limit(mut self) -> Self {
        self.max_steps = None;
        self
    }

    /// Enables trace capture for debugging.
    #[must_use]
    pub fn with_traces(mut self) -> Self {
        self.capture_traces = true;
        self
    }
}

/// Statistics about chaos injection during a test.
///
/// This is returned by `LabTestClient::chaos_stats()` after test execution.
#[derive(Debug, Clone, Default)]
pub struct TestChaosStats {
    /// Number of decision points encountered.
    pub decision_points: u64,
    /// Number of delays injected.
    pub delays_injected: u64,
    /// Number of cancellations injected.
    pub cancellations_injected: u64,
    /// Total steps executed.
    pub steps_executed: u64,
}

impl TestChaosStats {
    /// Returns the injection rate (injections / decision points).
    #[must_use]
    #[allow(clippy::cast_precision_loss)] // Acceptable for test stats
    pub fn injection_rate(&self) -> f64 {
        if self.decision_points == 0 {
            0.0
        } else {
            (self.delays_injected + self.cancellations_injected) as f64
                / self.decision_points as f64
        }
    }

    /// Returns true if any chaos was injected.
    #[must_use]
    pub fn had_chaos(&self) -> bool {
        self.delays_injected > 0 || self.cancellations_injected > 0
    }
}

/// Virtual time utilities for testing timeouts and delays.
///
/// This module provides helpers for simulating time passage in tests
/// without waiting for actual wall-clock time.
///
/// # Example
///
/// ```ignore
/// use fastapi_core::testing::MockTime;
///
/// let mock_time = MockTime::new();
///
/// // Advance virtual time by 5 seconds
/// mock_time.advance(Duration::from_secs(5));
///
/// // Check that timer has expired
/// assert!(mock_time.elapsed() >= Duration::from_secs(5));
/// ```
#[derive(Debug, Clone)]
pub struct MockTime {
    /// Current virtual time in microseconds.
    current_us: Arc<std::sync::atomic::AtomicU64>,
}

impl Default for MockTime {
    fn default() -> Self {
        Self::new()
    }
}

impl MockTime {
    /// Creates a new mock time starting at zero.
    #[must_use]
    pub fn new() -> Self {
        Self {
            current_us: Arc::new(std::sync::atomic::AtomicU64::new(0)),
        }
    }

    /// Creates a mock time starting at the given duration.
    #[must_use]
    pub fn starting_at(initial: std::time::Duration) -> Self {
        Self {
            current_us: Arc::new(std::sync::atomic::AtomicU64::new(initial.as_micros() as u64)),
        }
    }

    /// Returns the current virtual time.
    #[must_use]
    pub fn now(&self) -> std::time::Duration {
        std::time::Duration::from_micros(self.current_us.load(std::sync::atomic::Ordering::Relaxed))
    }

    /// Returns the elapsed time since creation.
    #[must_use]
    pub fn elapsed(&self) -> std::time::Duration {
        self.now()
    }

    /// Advances virtual time by the given duration.
    pub fn advance(&self, duration: std::time::Duration) {
        self.current_us.fetch_add(
            duration.as_micros() as u64,
            std::sync::atomic::Ordering::Relaxed,
        );
    }

    /// Sets virtual time to a specific value.
    pub fn set(&self, time: std::time::Duration) {
        self.current_us.store(
            time.as_micros() as u64,
            std::sync::atomic::Ordering::Relaxed,
        );
    }

    /// Resets virtual time to zero.
    pub fn reset(&self) {
        self.current_us
            .store(0, std::sync::atomic::Ordering::Relaxed);
    }
}

/// Result of a cancellation test.
///
/// Contains information about how the handler responded to cancellation.
#[derive(Debug)]
pub struct CancellationTestResult {
    /// Whether the handler completed before cancellation.
    pub completed: bool,
    /// Whether the handler detected cancellation via checkpoint.
    pub cancelled_at_checkpoint: bool,
    /// Response returned (if handler completed).
    pub response: Option<Response>,
    /// The await point at which cancellation was detected.
    pub cancellation_point: Option<String>,
}

impl CancellationTestResult {
    /// Returns true if cancellation was handled gracefully.
    #[must_use]
    pub fn gracefully_cancelled(&self) -> bool {
        !self.completed && self.cancelled_at_checkpoint
    }

    /// Returns true if the handler completed despite cancellation request.
    #[must_use]
    pub fn completed_despite_cancel(&self) -> bool {
        self.completed
    }
}

/// Helper for testing handler cancellation behavior.
///
/// # Example
///
/// ```ignore
/// use fastapi_core::testing::CancellationTest;
///
/// let test = CancellationTest::new(my_handler);
///
/// // Test that handler respects cancellation
/// let result = test.cancel_after_polls(3);
/// assert!(result.gracefully_cancelled());
/// ```
pub struct CancellationTest<H> {
    handler: H,
    seed: u64,
}

impl<H: Handler + 'static> CancellationTest<H> {
    /// Creates a new cancellation test for the given handler.
    #[must_use]
    pub fn new(handler: H) -> Self {
        Self { handler, seed: 42 }
    }

    /// Sets the seed for deterministic testing.
    #[must_use]
    pub fn with_seed(mut self, seed: u64) -> Self {
        self.seed = seed;
        self
    }

    /// Tests that the handler respects cancellation via checkpoint.
    ///
    /// This sets the cancellation flag before calling the handler, then
    /// verifies that the handler detects it at a checkpoint and returns
    /// an appropriate error response.
    pub fn test_respects_cancellation(&self) -> CancellationTestResult {
        let cx = asupersync::Cx::for_testing();
        let ctx = RequestContext::new(cx, 1);

        // Pre-set cancellation before handler runs
        ctx.cx().set_cancel_requested(true);

        let mut request = Request::new(Method::Get, "/test");
        let response = futures_executor::block_on(self.handler.call(&ctx, &mut request));

        // Check if handler returned a cancellation-related status
        let is_cancelled_response = response.status().as_u16() == 499
            || response.status().as_u16() == 504
            || response.status().as_u16() == 503;

        CancellationTestResult {
            completed: true,
            cancelled_at_checkpoint: is_cancelled_response,
            response: Some(response),
            cancellation_point: None,
        }
    }

    /// Tests that the handler completes normally without cancellation.
    pub fn complete_normally(&self) -> CancellationTestResult {
        let cx = asupersync::Cx::for_testing();
        let ctx = RequestContext::new(cx, 1);
        let mut request = Request::new(Method::Get, "/test");

        let response = futures_executor::block_on(self.handler.call(&ctx, &mut request));

        CancellationTestResult {
            completed: true,
            cancelled_at_checkpoint: false,
            response: Some(response),
            cancellation_point: None,
        }
    }

    /// Tests handler behavior with a custom cancellation callback.
    ///
    /// The callback is called with the context and can decide when
    /// to trigger cancellation based on custom logic.
    pub fn test_with_cancel_callback<F>(
        &self,
        path: &str,
        mut cancel_fn: F,
    ) -> CancellationTestResult
    where
        F: FnMut(&RequestContext) -> bool,
    {
        let cx = asupersync::Cx::for_testing();
        let ctx = RequestContext::new(cx, 1);

        // Call the cancel callback
        if cancel_fn(&ctx) {
            ctx.cx().set_cancel_requested(true);
        }

        let mut request = Request::new(Method::Get, path);
        let response = futures_executor::block_on(self.handler.call(&ctx, &mut request));

        let is_cancelled = ctx.is_cancelled();
        let is_cancelled_response =
            response.status().as_u16() == 499 || response.status().as_u16() == 504;

        CancellationTestResult {
            completed: true,
            cancelled_at_checkpoint: is_cancelled && is_cancelled_response,
            response: Some(response),
            cancellation_point: None,
        }
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::app::App;
    use crate::dependency::{Depends, FromDependency};
    use crate::error::HttpError;
    use crate::extract::FromRequest;
    use crate::middleware::BoxFuture;

    // Simple test handler
    struct EchoHandler;

    impl Handler for EchoHandler {
        fn call<'a>(
            &'a self,
            _ctx: &'a RequestContext,
            req: &'a mut Request,
        ) -> BoxFuture<'a, Response> {
            let method = format!("{:?}", req.method());
            let path = req.path().to_string();
            let body = format!("Method: {method}, Path: {path}");
            Box::pin(async move {
                Response::ok()
                    .header("content-type", b"text/plain".to_vec())
                    .body(ResponseBody::Bytes(body.into_bytes()))
            })
        }
    }

    // Handler that sets a cookie
    struct CookieHandler;

    impl Handler for CookieHandler {
        fn call<'a>(
            &'a self,
            _ctx: &'a RequestContext,
            _req: &'a mut Request,
        ) -> BoxFuture<'a, Response> {
            Box::pin(async move {
                Response::ok()
                    .header("set-cookie", b"session=abc123".to_vec())
                    .body(ResponseBody::Bytes(b"Cookie set".to_vec()))
            })
        }
    }

    // Handler that echoes the cookie
    struct CookieEchoHandler;

    impl Handler for CookieEchoHandler {
        fn call<'a>(
            &'a self,
            _ctx: &'a RequestContext,
            req: &'a mut Request,
        ) -> BoxFuture<'a, Response> {
            let cookie = req.headers().get("cookie").map_or_else(
                || "no cookies".to_string(),
                |v| String::from_utf8_lossy(v).to_string(),
            );
            Box::pin(async move { Response::ok().body(ResponseBody::Bytes(cookie.into_bytes())) })
        }
    }

    #[derive(Clone)]
    struct OverrideDep {
        value: usize,
    }

    impl FromDependency for OverrideDep {
        type Error = HttpError;

        async fn from_dependency(
            _ctx: &RequestContext,
            _req: &mut Request,
        ) -> Result<Self, Self::Error> {
            Ok(Self { value: 1 })
        }
    }

    struct OverrideDepHandler;

    impl Handler for OverrideDepHandler {
        fn call<'a>(
            &'a self,
            ctx: &'a RequestContext,
            req: &'a mut Request,
        ) -> BoxFuture<'a, Response> {
            Box::pin(async move {
                let dep = Depends::<OverrideDep>::from_request(ctx, req)
                    .await
                    .expect("dependency extraction failed");
                Response::ok().body(ResponseBody::Bytes(dep.value.to_string().into_bytes()))
            })
        }
    }

    fn override_dep_route(ctx: &RequestContext, req: &mut Request) -> std::future::Ready<Response> {
        let dep = futures_executor::block_on(Depends::<OverrideDep>::from_request(ctx, req))
            .expect("dependency extraction failed");
        std::future::ready(
            Response::ok().body(ResponseBody::Bytes(dep.value.to_string().into_bytes())),
        )
    }

    #[test]
    fn test_client_get() {
        let client = TestClient::new(EchoHandler);
        let response = client.get("/test/path").send();

        assert_eq!(response.status_code(), 200);
        assert_eq!(response.text(), "Method: Get, Path: /test/path");
    }

    #[test]
    fn test_client_post() {
        let client = TestClient::new(EchoHandler);
        let response = client.post("/api/items").send();

        assert_eq!(response.status_code(), 200);
        assert!(response.text().contains("Method: Post"));
    }

    // Note: This test is ignored because override_dep_route uses block_on internally,
    // which causes nested executor issues when TestClient::execute also uses block_on.
    // The same functionality is tested by test_test_client_override_clear using
    // the OverrideDepHandler struct which properly uses async/await.
    #[test]
    #[ignore = "nested executor issue: override_dep_route uses block_on inside TestClient's block_on"]
    fn test_app_dependency_override_used_by_test_client() {
        let app = App::builder()
            .route("/", Method::Get, override_dep_route)
            .build();

        app.override_dependency_value(OverrideDep { value: 42 });

        let client = TestClient::new(app);

        let response = client.get("/").send();

        assert_eq!(response.text(), "42");
    }

    #[test]
    fn test_test_client_override_clear() {
        let client = TestClient::new(OverrideDepHandler);

        client.override_dependency_value(OverrideDep { value: 9 });
        let response = client.get("/").send();
        assert_eq!(response.text(), "9");

        client.clear_dependency_overrides();
        let response = client.get("/").send();
        assert_eq!(response.text(), "1");
    }

    #[test]
    fn test_client_all_methods() {
        let client = TestClient::new(EchoHandler);

        assert!(client.get("/").send().text().contains("Get"));
        assert!(client.post("/").send().text().contains("Post"));
        assert!(client.put("/").send().text().contains("Put"));
        assert!(client.delete("/").send().text().contains("Delete"));
        assert!(client.patch("/").send().text().contains("Patch"));
        assert!(client.options("/").send().text().contains("Options"));
        assert!(client.head("/").send().text().contains("Head"));
    }

    #[test]
    fn test_query_params() {
        let client = TestClient::new(EchoHandler);
        let response = client
            .get("/search")
            .query("q", "rust")
            .query("limit", "10")
            .send();

        assert_eq!(response.status_code(), 200);
    }

    #[test]
    fn test_response_assertions() {
        let client = TestClient::new(EchoHandler);
        let response = client.get("/test").send();

        let _ = response
            .assert_status_code(200)
            .assert_success()
            .assert_header("content-type", "text/plain")
            .assert_text_contains("Get");
    }

    #[test]
    fn test_response_status_checks() {
        let client = TestClient::new(EchoHandler);
        let response = client.get("/").send();

        assert!(response.is_success());
        assert!(!response.is_redirect());
        assert!(!response.is_client_error());
        assert!(!response.is_server_error());
    }

    #[test]
    fn test_cookie_jar() {
        let mut jar = CookieJar::new();
        assert!(jar.is_empty());

        jar.set("session", "abc123");
        jar.set("user", "alice");

        assert_eq!(jar.len(), 2);
        assert_eq!(jar.get("session"), Some("abc123"));
        assert_eq!(jar.get("user"), Some("alice"));

        let header = jar.to_cookie_header().unwrap();
        assert!(header.contains("session=abc123"));
        assert!(header.contains("user=alice"));

        jar.remove("session");
        assert_eq!(jar.len(), 1);
        assert_eq!(jar.get("session"), None);
    }

    #[test]
    fn test_cookie_jar_request_matching_rules() {
        use crate::request::ConnectionInfo;

        let mut jar = CookieJar::new();

        let mut req = Request::new(Method::Get, "/account/settings");
        req.headers_mut().insert("host", b"example.com".to_vec());

        // Secure cookie should not be sent over non-secure request.
        jar.parse_set_cookie(
            &req,
            b"sid=1; Path=/account; Secure; HttpOnly; SameSite=Lax",
        );
        assert_eq!(jar.cookie_header_for_request(&req), None);

        // Mark request as TLS-enabled; now it matches.
        req.insert_extension(ConnectionInfo::HTTPS);
        assert_eq!(
            jar.cookie_header_for_request(&req).as_deref(),
            Some("sid=1")
        );

        // Path mismatch should prevent sending.
        let mut req2 = Request::new(Method::Get, "/other");
        req2.headers_mut().insert("host", b"example.com".to_vec());
        req2.insert_extension(ConnectionInfo::HTTPS);
        assert_eq!(jar.cookie_header_for_request(&req2), None);

        // Domain cookies should match subdomains.
        jar.parse_set_cookie(&req, b"sub=1; Domain=example.com; Path=/");
        let mut req3 = Request::new(Method::Get, "/");
        req3.headers_mut()
            .insert("host", b"api.example.com".to_vec());
        let hdr = jar.cookie_header_for_request(&req3).expect("cookie header");
        assert!(hdr.contains("sub=1"));
    }

    #[test]
    fn test_cookie_persistence() {
        let client = TestClient::new(CookieHandler);

        // First request sets a cookie
        let _ = client.get("/set-cookie").send();

        // Cookie should be in the jar
        assert_eq!(client.cookies().get("session"), Some("abc123"));

        // Use a new handler that echoes cookies
        let client2 = TestClient::new(CookieEchoHandler);
        client2.cookies().set("session", "abc123");

        let response = client2.get("/check-cookie").send();
        assert!(response.text().contains("session=abc123"));
    }

    #[test]
    fn test_request_id_increments() {
        let client = TestClient::new(EchoHandler);

        let r1 = client.get("/").send();
        let r2 = client.get("/").send();
        let r3 = client.get("/").send();

        assert_eq!(r1.request_id(), 1);
        assert_eq!(r2.request_id(), 2);
        assert_eq!(r3.request_id(), 3);
    }

    #[test]
    fn test_client_with_seed() {
        let client = TestClient::with_seed(EchoHandler, 42);
        assert_eq!(client.seed(), Some(42));
    }

    #[test]
    fn test_client_clone() {
        let client = TestClient::new(EchoHandler);
        client.cookies().set("test", "value");

        let cloned = client.clone();

        // Cloned client shares cookies
        assert_eq!(cloned.cookies().get("test"), Some("value"));

        // And request ID counter
        let r1 = client.get("/").send();
        let r2 = cloned.get("/").send();
        assert_eq!(r1.request_id(), 1);
        assert_eq!(r2.request_id(), 2);
    }

    // =========================================================================
    // Tests for json_contains partial matching
    // =========================================================================

    #[test]
    fn test_json_contains_exact_match() {
        let actual = serde_json::json!({"id": 1, "name": "Alice"});
        let expected = serde_json::json!({"id": 1, "name": "Alice"});
        assert!(json_contains(&actual, &expected).is_ok());
    }

    #[test]
    fn test_json_contains_partial_match() {
        let actual = serde_json::json!({"id": 1, "name": "Alice", "email": "alice@example.com"});
        let expected = serde_json::json!({"name": "Alice"});
        assert!(json_contains(&actual, &expected).is_ok());
    }

    #[test]
    fn test_json_contains_nested_partial_match() {
        let actual = serde_json::json!({
            "user": {"id": 1, "name": "Alice", "email": "alice@example.com"},
            "status": "active"
        });
        let expected = serde_json::json!({
            "user": {"name": "Alice"}
        });
        assert!(json_contains(&actual, &expected).is_ok());
    }

    #[test]
    fn test_json_contains_mismatch_value() {
        let actual = serde_json::json!({"id": 1, "name": "Alice"});
        let expected = serde_json::json!({"name": "Bob"});
        let result = json_contains(&actual, &expected);
        assert!(result.is_err());
        assert_eq!(result.unwrap_err(), "$.name");
    }

    #[test]
    fn test_json_contains_missing_key() {
        let actual = serde_json::json!({"id": 1, "name": "Alice"});
        let expected = serde_json::json!({"email": "alice@example.com"});
        let result = json_contains(&actual, &expected);
        assert!(result.is_err());
        assert_eq!(result.unwrap_err(), "$.email");
    }

    #[test]
    fn test_json_contains_array_exact_match() {
        let actual = serde_json::json!({"items": [1, 2, 3]});
        let expected = serde_json::json!({"items": [1, 2, 3]});
        assert!(json_contains(&actual, &expected).is_ok());
    }

    #[test]
    fn test_json_contains_array_length_mismatch() {
        let actual = serde_json::json!({"items": [1, 2, 3]});
        let expected = serde_json::json!({"items": [1, 2]});
        let result = json_contains(&actual, &expected);
        assert!(result.is_err());
        assert_eq!(result.unwrap_err(), "$.items[length]");
    }

    #[test]
    fn test_json_contains_array_element_mismatch() {
        let actual = serde_json::json!({"items": [1, 2, 3]});
        let expected = serde_json::json!({"items": [1, 5, 3]});
        let result = json_contains(&actual, &expected);
        assert!(result.is_err());
        assert_eq!(result.unwrap_err(), "$.items[1]");
    }

    #[test]
    fn test_json_contains_primitives() {
        // Numbers
        assert!(json_contains(&serde_json::json!(42), &serde_json::json!(42)).is_ok());
        assert!(json_contains(&serde_json::json!(42), &serde_json::json!(43)).is_err());

        // Strings
        assert!(json_contains(&serde_json::json!("hello"), &serde_json::json!("hello")).is_ok());
        assert!(json_contains(&serde_json::json!("hello"), &serde_json::json!("world")).is_err());

        // Booleans
        assert!(json_contains(&serde_json::json!(true), &serde_json::json!(true)).is_ok());
        assert!(json_contains(&serde_json::json!(true), &serde_json::json!(false)).is_err());

        // Null
        assert!(json_contains(&serde_json::json!(null), &serde_json::json!(null)).is_ok());
    }

    #[test]
    fn test_json_contains_type_mismatch() {
        let actual = serde_json::json!({"id": "1"});
        let expected = serde_json::json!({"id": 1});
        let result = json_contains(&actual, &expected);
        assert!(result.is_err());
        assert_eq!(result.unwrap_err(), "$.id");
    }

    #[test]
    fn test_json_contains_deeply_nested() {
        let actual = serde_json::json!({
            "level1": {
                "level2": {
                    "level3": {
                        "value": 42,
                        "extra": "ignored"
                    }
                }
            }
        });
        let expected = serde_json::json!({
            "level1": {
                "level2": {
                    "level3": {
                        "value": 42
                    }
                }
            }
        });
        assert!(json_contains(&actual, &expected).is_ok());
    }

    // =========================================================================
    // Tests for assertion macros using handler that returns JSON
    // =========================================================================

    // Handler that returns JSON
    struct JsonHandler;

    impl Handler for JsonHandler {
        fn call<'a>(
            &'a self,
            _ctx: &'a RequestContext,
            _req: &'a mut Request,
        ) -> BoxFuture<'a, Response> {
            let json = serde_json::json!({
                "id": 1,
                "name": "Alice",
                "email": "alice@example.com",
                "active": true
            });
            let body = serde_json::to_vec(&json).unwrap();
            Box::pin(async move {
                Response::ok()
                    .header("content-type", b"application/json".to_vec())
                    .header("x-request-id", b"req-123".to_vec())
                    .body(ResponseBody::Bytes(body))
            })
        }
    }

    // Handler that returns a specific status code
    #[allow(dead_code)]
    struct StatusHandler(u16);

    #[allow(dead_code)]
    impl Handler for StatusHandler {
        fn call<'a>(
            &'a self,
            _ctx: &'a RequestContext,
            _req: &'a mut Request,
        ) -> BoxFuture<'a, Response> {
            let status = StatusCode::from_u16(self.0);
            Box::pin(async move { Response::with_status(status) })
        }
    }

    #[test]
    fn test_assert_status_macro_with_u16() {
        let client = TestClient::new(EchoHandler);
        let response = client.get("/").send();
        crate::assert_status!(response, 200);
    }

    #[test]
    fn test_assert_status_macro_with_status_code() {
        let client = TestClient::new(EchoHandler);
        let response = client.get("/").send();
        crate::assert_status!(response, StatusCode::OK);
    }

    #[test]
    #[should_panic(expected = "assertion failed")]
    fn test_assert_status_macro_failure() {
        let client = TestClient::new(EchoHandler);
        let response = client.get("/").send();
        crate::assert_status!(response, 404);
    }

    #[test]
    fn test_assert_header_macro() {
        let client = TestClient::new(EchoHandler);
        let response = client.get("/").send();
        crate::assert_header!(response, "content-type", "text/plain");
    }

    #[test]
    #[should_panic(expected = "assertion failed")]
    fn test_assert_header_macro_failure() {
        let client = TestClient::new(EchoHandler);
        let response = client.get("/").send();
        crate::assert_header!(response, "content-type", "application/json");
    }

    #[test]
    fn test_assert_body_contains_macro() {
        let client = TestClient::new(EchoHandler);
        let response = client.get("/test").send();
        crate::assert_body_contains!(response, "Method: Get");
        crate::assert_body_contains!(response, "Path: /test");
    }

    #[test]
    #[should_panic(expected = "assertion failed")]
    fn test_assert_body_contains_macro_failure() {
        let client = TestClient::new(EchoHandler);
        let response = client.get("/test").send();
        crate::assert_body_contains!(response, "nonexistent");
    }

    #[test]
    fn test_assert_json_macro_partial_match() {
        let client = TestClient::new(JsonHandler);
        let response = client.get("/user").send();

        // Partial match - only check some fields
        crate::assert_json!(response, {"name": "Alice"});
        crate::assert_json!(response, {"id": 1, "active": true});
    }

    #[test]
    fn test_assert_json_macro_exact_match() {
        let client = TestClient::new(JsonHandler);
        let response = client.get("/user").send();

        // Exact match - all fields
        crate::assert_json!(response, {
            "id": 1,
            "name": "Alice",
            "email": "alice@example.com",
            "active": true
        });
    }

    #[test]
    #[should_panic(expected = "JSON partial match failed")]
    fn test_assert_json_macro_failure() {
        let client = TestClient::new(JsonHandler);
        let response = client.get("/user").send();
        crate::assert_json!(response, {"name": "Bob"});
    }

    // =========================================================================
    // Tests for method-based assertions
    // =========================================================================

    #[test]
    fn test_assert_json_contains_method() {
        let client = TestClient::new(JsonHandler);
        let response = client.get("/user").send();

        let _ = response.assert_json_contains(&serde_json::json!({"name": "Alice"}));
    }

    #[test]
    fn test_assert_header_exists() {
        let client = TestClient::new(JsonHandler);
        let response = client.get("/").send();

        let _ = response
            .assert_header_exists("content-type")
            .assert_header_exists("x-request-id");
    }

    #[test]
    #[should_panic(expected = "Expected header 'nonexistent' to exist")]
    fn test_assert_header_exists_failure() {
        let client = TestClient::new(JsonHandler);
        let response = client.get("/").send();
        let _ = response.assert_header_exists("nonexistent");
    }

    #[test]
    fn test_assert_header_missing() {
        let client = TestClient::new(JsonHandler);
        let response = client.get("/").send();

        let _ = response.assert_header_missing("x-nonexistent");
    }

    #[test]
    #[should_panic(expected = "Expected header 'content-type' to not exist")]
    fn test_assert_header_missing_failure() {
        let client = TestClient::new(JsonHandler);
        let response = client.get("/").send();
        let _ = response.assert_header_missing("content-type");
    }

    #[test]
    fn test_assert_content_type_contains() {
        let client = TestClient::new(JsonHandler);
        let response = client.get("/").send();

        let _ = response.assert_content_type_contains("application/json");
        let _ = response.assert_content_type_contains("json");
    }

    #[test]
    #[should_panic(expected = "Expected Content-Type to contain")]
    fn test_assert_content_type_contains_failure() {
        let client = TestClient::new(JsonHandler);
        let response = client.get("/").send();
        let _ = response.assert_content_type_contains("text/html");
    }

    #[test]
    fn test_assertion_chaining() {
        let client = TestClient::new(JsonHandler);
        let response = client.get("/user").send();

        // All assertions can be chained
        let _ = response
            .assert_status_code(200)
            .assert_success()
            .assert_header_exists("content-type")
            .assert_content_type_contains("json")
            .assert_json_contains(&serde_json::json!({"name": "Alice"}));
    }

    #[test]
    fn test_macro_with_custom_message() {
        let client = TestClient::new(EchoHandler);
        let response = client.get("/").send();

        // These should pass (custom message only shown on failure)
        crate::assert_status!(response, 200, "Expected 200 OK from echo handler");
        crate::assert_header!(
            response,
            "content-type",
            "text/plain",
            "Should have text content type"
        );
        crate::assert_body_contains!(response, "Get", "Should contain HTTP method");
    }

    // =========================================================================
    // DI Integration Tests (fastapi_rust-zf4)
    // =========================================================================

    // Test complex nested dependency graph with App and TestClient
    #[derive(Clone)]
    struct DatabasePool {
        connection_string: String,
    }

    impl FromDependency for DatabasePool {
        type Error = HttpError;
        async fn from_dependency(
            _ctx: &RequestContext,
            _req: &mut Request,
        ) -> Result<Self, Self::Error> {
            Ok(DatabasePool {
                connection_string: "postgres://localhost/test".to_string(),
            })
        }
    }

    #[derive(Clone)]
    struct UserRepository {
        pool_conn_str: String,
    }

    impl FromDependency for UserRepository {
        type Error = HttpError;
        async fn from_dependency(
            ctx: &RequestContext,
            req: &mut Request,
        ) -> Result<Self, Self::Error> {
            let pool = Depends::<DatabasePool>::from_request(ctx, req).await?;
            Ok(UserRepository {
                pool_conn_str: pool.connection_string.clone(),
            })
        }
    }

    #[derive(Clone)]
    struct AuthService {
        user_repo_pool: String,
    }

    impl FromDependency for AuthService {
        type Error = HttpError;
        async fn from_dependency(
            ctx: &RequestContext,
            req: &mut Request,
        ) -> Result<Self, Self::Error> {
            let repo = Depends::<UserRepository>::from_request(ctx, req).await?;
            Ok(AuthService {
                user_repo_pool: repo.pool_conn_str.clone(),
            })
        }
    }

    struct ComplexDepHandler;

    impl Handler for ComplexDepHandler {
        fn call<'a>(
            &'a self,
            ctx: &'a RequestContext,
            req: &'a mut Request,
        ) -> BoxFuture<'a, Response> {
            Box::pin(async move {
                let auth = Depends::<AuthService>::from_request(ctx, req)
                    .await
                    .expect("dependency resolution failed");
                let body = format!("AuthService.pool={}", auth.user_repo_pool);
                Response::ok().body(ResponseBody::Bytes(body.into_bytes()))
            })
        }
    }

    #[test]
    fn test_full_request_with_complex_deps() {
        // Test a realistic handler with nested dependencies:
        // Handler -> AuthService -> UserRepository -> DatabasePool
        let client = TestClient::new(ComplexDepHandler);
        let response = client.get("/auth/check").send();

        assert_eq!(response.status_code(), 200);
        assert!(response.text().contains("postgres://localhost/test"));
    }

    #[test]
    fn test_complex_deps_with_override_at_leaf() {
        // Override the leaf dependency (DatabasePool) and verify it propagates
        let client = TestClient::new(ComplexDepHandler);
        client.override_dependency_value(DatabasePool {
            connection_string: "mysql://prod/users".to_string(),
        });

        let response = client.get("/auth/check").send();

        assert_eq!(response.status_code(), 200);
        assert!(
            response.text().contains("mysql://prod/users"),
            "Override at leaf should propagate through dependency chain"
        );
    }

    #[test]
    fn test_complex_deps_with_override_at_middle() {
        // Override the middle dependency (UserRepository)
        let client = TestClient::new(ComplexDepHandler);
        client.override_dependency_value(UserRepository {
            pool_conn_str: "overridden-repo-connection".to_string(),
        });

        let response = client.get("/auth/check").send();

        assert_eq!(response.status_code(), 200);
        assert!(
            response.text().contains("overridden-repo-connection"),
            "Override at middle level should be used"
        );
    }

    #[test]
    fn test_dependency_caching_across_handler() {
        // Test that dependencies are cached within a single request
        use std::sync::atomic::{AtomicUsize, Ordering};

        static CALL_COUNT: AtomicUsize = AtomicUsize::new(0);

        #[derive(Clone)]
        struct TrackedDep {
            call_number: usize,
        }

        impl FromDependency for TrackedDep {
            type Error = HttpError;
            async fn from_dependency(
                _ctx: &RequestContext,
                _req: &mut Request,
            ) -> Result<Self, Self::Error> {
                let call_number = CALL_COUNT.fetch_add(1, Ordering::SeqCst);
                Ok(TrackedDep { call_number })
            }
        }

        struct MultiDepHandler;

        impl Handler for MultiDepHandler {
            fn call<'a>(
                &'a self,
                ctx: &'a RequestContext,
                req: &'a mut Request,
            ) -> BoxFuture<'a, Response> {
                Box::pin(async move {
                    // Request the same dependency twice
                    let dep1 = Depends::<TrackedDep>::from_request(ctx, req)
                        .await
                        .expect("first resolution failed");
                    let dep2 = Depends::<TrackedDep>::from_request(ctx, req)
                        .await
                        .expect("second resolution failed");

                    // Both should be the same (cached)
                    let body = format!("dep1={} dep2={}", dep1.call_number, dep2.call_number);
                    Response::ok().body(ResponseBody::Bytes(body.into_bytes()))
                })
            }
        }

        // Reset counter
        CALL_COUNT.store(0, Ordering::SeqCst);

        let client = TestClient::new(MultiDepHandler);
        let response = client.get("/").send();

        let text = response.text();
        // Both deps should have the same call number (cached)
        assert!(
            text.contains("dep1=0 dep2=0"),
            "Dependencies should be cached within request. Got: {}",
            text
        );

        // Counter should only have been incremented once
        assert_eq!(CALL_COUNT.load(Ordering::SeqCst), 1);
    }

    // =========================================================================
    // Lab Runtime Testing Utilities Tests
    // =========================================================================

    #[test]
    #[allow(clippy::float_cmp)] // Comparing exact literals is safe
    fn lab_test_config_defaults() {
        let config = LabTestConfig::default();
        assert_eq!(config.seed, 42);
        assert!(!config.chaos_enabled);
        assert_eq!(config.chaos_intensity, 0.0);
        assert_eq!(config.max_steps, Some(10_000));
        assert!(!config.capture_traces);
    }

    #[test]
    fn lab_test_config_with_seed() {
        let config = LabTestConfig::new(12345);
        assert_eq!(config.seed, 12345);
    }

    #[test]
    #[allow(clippy::float_cmp)] // Comparing exact literals is safe
    fn lab_test_config_light_chaos() {
        let config = LabTestConfig::new(42).with_light_chaos();
        assert!(config.chaos_enabled);
        assert_eq!(config.chaos_intensity, 0.05);
    }

    #[test]
    #[allow(clippy::float_cmp)] // Comparing exact literals is safe
    fn lab_test_config_heavy_chaos() {
        let config = LabTestConfig::new(42).with_heavy_chaos();
        assert!(config.chaos_enabled);
        assert_eq!(config.chaos_intensity, 0.2);
    }

    #[test]
    #[allow(clippy::float_cmp)] // Comparing exact literals is safe
    fn lab_test_config_custom_intensity() {
        let config = LabTestConfig::new(42).with_chaos_intensity(0.15);
        assert!(config.chaos_enabled);
        assert_eq!(config.chaos_intensity, 0.15);
    }

    #[test]
    #[allow(clippy::float_cmp)] // Comparing exact literals is safe
    fn lab_test_config_intensity_clamps() {
        let config = LabTestConfig::new(42).with_chaos_intensity(1.5);
        assert_eq!(config.chaos_intensity, 1.0);

        let config = LabTestConfig::new(42).with_chaos_intensity(-0.5);
        assert_eq!(config.chaos_intensity, 0.0);
        assert!(!config.chaos_enabled);
    }

    #[test]
    fn lab_test_config_max_steps() {
        let config = LabTestConfig::new(42).with_max_steps(1000);
        assert_eq!(config.max_steps, Some(1000));
    }

    #[test]
    fn lab_test_config_no_step_limit() {
        let config = LabTestConfig::new(42).without_step_limit();
        assert_eq!(config.max_steps, None);
    }

    #[test]
    fn lab_test_config_with_traces() {
        let config = LabTestConfig::new(42).with_traces();
        assert!(config.capture_traces);
    }

    #[test]
    #[allow(clippy::float_cmp)] // Comparing exact 0.0 is safe
    fn test_chaos_stats_empty() {
        let stats = TestChaosStats::default();
        assert_eq!(stats.decision_points, 0);
        assert_eq!(stats.delays_injected, 0);
        assert_eq!(stats.cancellations_injected, 0);
        assert_eq!(stats.injection_rate(), 0.0);
        assert!(!stats.had_chaos());
    }

    #[test]
    fn test_chaos_stats_with_injections() {
        let stats = TestChaosStats {
            decision_points: 100,
            delays_injected: 5,
            cancellations_injected: 2,
            steps_executed: 50,
        };
        assert!((stats.injection_rate() - 0.07).abs() < 0.001);
        assert!(stats.had_chaos());
    }

    #[test]
    fn mock_time_basic() {
        let time = MockTime::new();
        assert_eq!(time.now(), std::time::Duration::ZERO);
        assert_eq!(time.elapsed(), std::time::Duration::ZERO);

        time.advance(std::time::Duration::from_secs(5));
        assert_eq!(time.now(), std::time::Duration::from_secs(5));
    }

    #[test]
    fn mock_time_set_and_reset() {
        let time = MockTime::new();
        time.set(std::time::Duration::from_secs(100));
        assert_eq!(time.now(), std::time::Duration::from_secs(100));

        time.reset();
        assert_eq!(time.now(), std::time::Duration::ZERO);
    }

    #[test]
    fn mock_time_starting_at() {
        let time = MockTime::starting_at(std::time::Duration::from_secs(10));
        assert_eq!(time.now(), std::time::Duration::from_secs(10));
    }

    #[test]
    fn cancellation_test_completes_normally() {
        let test = CancellationTest::new(EchoHandler);
        let result = test.complete_normally();

        assert!(result.completed);
        assert!(!result.cancelled_at_checkpoint);
        assert!(result.response.is_some());
        assert_eq!(result.response.as_ref().unwrap().status().as_u16(), 200);
    }

    #[test]
    fn cancellation_test_respects_cancellation() {
        // Handler that checks cancellation via checkpoint
        struct CheckpointHandler;

        impl Handler for CheckpointHandler {
            fn call<'a>(
                &'a self,
                ctx: &'a RequestContext,
                _req: &'a mut Request,
            ) -> BoxFuture<'a, Response> {
                Box::pin(async move {
                    // Check for cancellation
                    if ctx.checkpoint().is_err() {
                        return Response::with_status(StatusCode::CLIENT_CLOSED_REQUEST);
                    }
                    Response::ok().body(ResponseBody::Bytes(b"OK".to_vec()))
                })
            }
        }

        let test = CancellationTest::new(CheckpointHandler);
        let result = test.test_respects_cancellation();

        assert!(result.completed);
        assert!(result.cancelled_at_checkpoint);
        assert!(result.response.is_some());
        // Should return 499 (CLIENT_CLOSED_REQUEST) when cancelled
        assert_eq!(result.response.as_ref().unwrap().status().as_u16(), 499);
    }

    #[test]
    fn cancellation_test_result_helpers() {
        let graceful = CancellationTestResult {
            completed: false,
            cancelled_at_checkpoint: true,
            response: None,
            cancellation_point: None,
        };
        assert!(graceful.gracefully_cancelled());
        assert!(!graceful.completed_despite_cancel());

        let completed = CancellationTestResult {
            completed: true,
            cancelled_at_checkpoint: false,
            response: Some(Response::ok()),
            cancellation_point: None,
        };
        assert!(!completed.gracefully_cancelled());
        assert!(completed.completed_despite_cancel());
    }

    // =========================================================================
    // Tests for TestLogger and LogCapture (bd-2of7)
    // =========================================================================

    #[test]
    fn test_logger_captures_all_levels() {
        let logger = TestLogger::new();

        logger.log_message(LogLevel::Debug, "debug message", 1);
        logger.log_message(LogLevel::Info, "info message", 1);
        logger.log_message(LogLevel::Warn, "warn message", 1);
        logger.log_message(LogLevel::Error, "error message", 1);

        let logs = logger.logs();
        assert_eq!(logs.len(), 4);

        assert_eq!(logs[0].level, LogLevel::Debug);
        assert_eq!(logs[1].level, LogLevel::Info);
        assert_eq!(logs[2].level, LogLevel::Warn);
        assert_eq!(logs[3].level, LogLevel::Error);
    }

    #[test]
    fn test_logger_logs_at_level_filters_correctly() {
        let logger = TestLogger::new();

        logger.log_message(LogLevel::Debug, "debug", 1);
        logger.log_message(LogLevel::Info, "info 1", 1);
        logger.log_message(LogLevel::Info, "info 2", 2);
        logger.log_message(LogLevel::Warn, "warn", 1);
        logger.log_message(LogLevel::Error, "error", 1);

        let info_logs = logger.logs_at_level(LogLevel::Info);
        assert_eq!(info_logs.len(), 2);
        assert!(info_logs[0].contains("info 1"));
        assert!(info_logs[1].contains("info 2"));

        let error_logs = logger.logs_at_level(LogLevel::Error);
        assert_eq!(error_logs.len(), 1);
        assert!(error_logs[0].contains("error"));

        let trace_logs = logger.logs_at_level(LogLevel::Trace);
        assert_eq!(trace_logs.len(), 0);
    }

    #[test]
    fn test_logger_contains_message_search() {
        let logger = TestLogger::new();

        logger.log_message(LogLevel::Info, "User alice logged in", 100);
        logger.log_message(LogLevel::Info, "Request processed for /api/users", 101);
        logger.log_message(LogLevel::Warn, "Rate limit approaching for alice", 102);

        assert!(logger.contains_message("alice"));
        assert!(logger.contains_message("/api/users"));
        assert!(logger.contains_message("Rate limit"));
        assert!(!logger.contains_message("bob"));
        assert!(!logger.contains_message("nonexistent"));
    }

    #[test]
    fn test_logger_contains_multiple_messages() {
        let logger = TestLogger::new();

        logger.log_message(LogLevel::Info, "step 1 complete", 1);
        logger.log_message(LogLevel::Info, "step 2 complete", 2);
        logger.log_message(LogLevel::Info, "step 3 complete", 3);

        // All messages should be findable
        assert!(logger.contains_message("step 1"));
        assert!(logger.contains_message("step 2"));
        assert!(logger.contains_message("step 3"));
        assert!(logger.contains_message("complete"));
        // Non-existent message
        assert!(!logger.contains_message("step 4"));
    }

    #[test]
    fn test_log_capture_captures_logs_in_closure() {
        let capture = TestLogger::capture(|logger| {
            logger.log_message(LogLevel::Info, "inside capture", 1);
            logger.log_message(LogLevel::Warn, "warning inside", 2);
            42
        });

        assert!(capture.passed());
        assert!(!capture.failed());
        assert_eq!(capture.result, Some(42));
        assert_eq!(capture.logs.len(), 2);
        assert!(capture.contains_message("inside capture"));
        assert!(capture.contains_message("warning inside"));
    }

    #[test]
    fn test_log_capture_count_by_level() {
        let capture = TestLogger::capture(|logger| {
            logger.log_message(LogLevel::Info, "info 1", 1);
            logger.log_message(LogLevel::Info, "info 2", 2);
            logger.log_message(LogLevel::Info, "info 3", 3);
            logger.log_message(LogLevel::Error, "error 1", 4);
        });

        assert_eq!(capture.count_by_level(LogLevel::Info), 3);
        assert_eq!(capture.count_by_level(LogLevel::Error), 1);
        assert_eq!(capture.count_by_level(LogLevel::Warn), 0);
    }

    #[test]
    fn test_log_capture_phased_all_phases() {
        let capture = TestLogger::capture_phased(
            |logger| {
                logger.log_message(LogLevel::Info, "setup phase", 1);
            },
            |logger| {
                logger.log_message(LogLevel::Info, "execute phase", 2);
                "result"
            },
            |logger| {
                logger.log_message(LogLevel::Info, "teardown phase", 3);
            },
        );

        assert!(capture.passed());
        assert_eq!(capture.result, Some("result"));
        assert_eq!(capture.logs.len(), 3);
        assert!(capture.contains_message("setup phase"));
        assert!(capture.contains_message("execute phase"));
        assert!(capture.contains_message("teardown phase"));
    }

    #[test]
    fn test_log_capture_timings_recorded() {
        let capture = TestLogger::capture(|_logger| {
            // Small computation to ensure measurable time
            let mut sum = 0;
            for i in 0..1000 {
                sum += i;
            }
            sum
        });

        assert!(capture.passed());
        // Timings should be recorded (may be very small but non-negative)
        let timings = &capture.timings;
        assert!(timings.total() >= std::time::Duration::ZERO);
    }

    #[test]
    fn test_log_capture_failure_context() {
        let capture = TestLogger::capture(|logger| {
            logger.log_message(LogLevel::Info, "step 1", 1);
            logger.log_message(LogLevel::Info, "step 2", 2);
            logger.log_message(LogLevel::Error, "something went wrong", 3);
            logger.log_message(LogLevel::Info, "step 3", 4);
        });

        let context = capture.failure_context(3);
        // Should contain the last 3 logs
        assert!(context.contains("something went wrong") || context.contains("step 3"));
    }

    #[test]
    fn test_captured_log_format() {
        let log = CapturedLog::new(LogLevel::Warn, "test warning message", 12345);

        let formatted = log.format();
        // Format is "[W] req=12345 test warning message" for Warn level
        assert!(formatted.contains("[W]"));
        assert!(formatted.contains("test warning message"));
        assert!(formatted.contains("12345"));
    }

    #[test]
    fn test_captured_log_contains() {
        let log = CapturedLog::new(LogLevel::Info, "user login successful for alice", 1);

        assert!(log.contains("login"));
        assert!(log.contains("alice"));
        assert!(log.contains("successful"));
        assert!(!log.contains("bob"));
        assert!(!log.contains("failed"));
    }

    #[test]
    fn test_captured_log_fields() {
        let log = CapturedLog::new(LogLevel::Error, "database connection failed", 999);

        assert_eq!(log.level, LogLevel::Error);
        assert_eq!(log.message, "database connection failed");
        assert_eq!(log.request_id, 999);
    }

    #[test]
    fn test_multiple_loggers_isolated() {
        let logger1 = TestLogger::new();
        let logger2 = TestLogger::new();

        logger1.log_message(LogLevel::Info, "from logger 1", 1);
        logger2.log_message(LogLevel::Info, "from logger 2", 2);

        assert_eq!(logger1.logs().len(), 1);
        assert_eq!(logger2.logs().len(), 1);
        assert!(logger1.contains_message("logger 1"));
        assert!(!logger1.contains_message("logger 2"));
        assert!(logger2.contains_message("logger 2"));
        assert!(!logger2.contains_message("logger 1"));
    }

    #[test]
    fn test_logger_log_entry_integration() {
        let logger = TestLogger::new();

        let entry = LogEntry {
            level: LogLevel::Warn,
            message: "warning from entry".to_string(),
            request_id: 42,
            region_id: "region-1".to_string(),
            task_id: "task-1".to_string(),
            target: None,
            fields: Vec::new(),
            timestamp_ns: 0,
        };

        logger.log_entry(&entry);

        assert_eq!(logger.logs().len(), 1);
        let captured = &logger.logs()[0];
        assert_eq!(captured.level, LogLevel::Warn);
        assert!(captured.contains("warning from entry"));
        assert_eq!(captured.request_id, 42);
    }

    #[test]
    fn test_log_capture_unwrap_on_success() {
        let capture = TestLogger::capture(|_| 123);
        let value = capture.unwrap();
        assert_eq!(value, 123);
    }

    #[test]
    fn test_log_capture_unwrap_or_on_success() {
        let capture = TestLogger::capture(|_| 456);
        let value = capture.unwrap_or(0);
        assert_eq!(value, 456);
    }
}

// =============================================================================
// MockServer for Integration Testing
// =============================================================================

use std::io::{Read as _, Write as _};
use std::net::{SocketAddr, TcpListener as StdTcpListener, TcpStream as StdTcpStream};
use std::sync::atomic::AtomicBool;
use std::thread;
use std::time::Duration;

/// A recorded request from the mock server.
///
/// Contains all information about a request that was made to the mock server,
/// useful for asserting that expected requests were made.
#[derive(Debug, Clone)]
pub struct RecordedRequest {
    /// The HTTP method (GET, POST, etc.)
    pub method: String,
    /// The request path (e.g., "/api/users")
    pub path: String,
    /// Query string if present (without the leading '?')
    pub query: Option<String>,
    /// Request headers as name-value pairs
    pub headers: Vec<(String, String)>,
    /// Request body as bytes
    pub body: Vec<u8>,
    /// Timestamp when the request was received
    pub timestamp: std::time::Instant,
}

impl RecordedRequest {
    /// Returns the request body as a UTF-8 string.
    ///
    /// # Panics
    ///
    /// Panics if the body is not valid UTF-8.
    #[must_use]
    pub fn body_text(&self) -> &str {
        std::str::from_utf8(&self.body).expect("body is not valid UTF-8")
    }

    /// Returns a header value by name (case-insensitive).
    #[must_use]
    pub fn header(&self, name: &str) -> Option<&str> {
        let name_lower = name.to_ascii_lowercase();
        self.headers
            .iter()
            .find(|(n, _)| n.to_ascii_lowercase() == name_lower)
            .map(|(_, v)| v.as_str())
    }

    /// Returns the full URL including query string.
    #[must_use]
    pub fn url(&self) -> String {
        match &self.query {
            Some(q) => format!("{}?{}", self.path, q),
            None => self.path.clone(),
        }
    }
}

/// Configuration for a canned response.
#[derive(Debug, Clone)]
pub struct MockResponse {
    /// HTTP status code
    pub status: u16,
    /// Response headers
    pub headers: Vec<(String, String)>,
    /// Response body
    pub body: Vec<u8>,
    /// Optional delay before sending response
    pub delay: Option<Duration>,
}

impl Default for MockResponse {
    fn default() -> Self {
        Self {
            status: 200,
            headers: vec![("content-type".to_string(), "text/plain".to_string())],
            body: b"OK".to_vec(),
            delay: None,
        }
    }
}

impl MockResponse {
    /// Creates a new mock response with 200 OK status.
    #[must_use]
    pub fn ok() -> Self {
        Self::default()
    }

    /// Creates a mock response with the given status code.
    #[must_use]
    pub fn with_status(status: u16) -> Self {
        Self {
            status,
            ..Default::default()
        }
    }

    /// Sets the response status code.
    #[must_use]
    pub fn status(mut self, status: u16) -> Self {
        self.status = status;
        self
    }

    /// Adds a header to the response.
    #[must_use]
    pub fn header(mut self, name: impl Into<String>, value: impl Into<String>) -> Self {
        self.headers.push((name.into(), value.into()));
        self
    }

    /// Sets the response body.
    #[must_use]
    pub fn body(mut self, body: impl Into<Vec<u8>>) -> Self {
        self.body = body.into();
        self
    }

    /// Sets the response body as a string.
    #[must_use]
    pub fn body_str(self, body: &str) -> Self {
        self.body(body.as_bytes().to_vec())
    }

    /// Sets the response body as JSON.
    #[must_use]
    pub fn json<T: serde::Serialize>(mut self, value: &T) -> Self {
        self.body = serde_json::to_vec(value).expect("JSON serialization failed");
        self.headers
            .push(("content-type".to_string(), "application/json".to_string()));
        self
    }

    /// Sets a delay before sending the response.
    #[must_use]
    pub fn delay(mut self, duration: Duration) -> Self {
        self.delay = Some(duration);
        self
    }

    /// Formats the response as an HTTP response string.
    fn to_http_response(&self) -> Vec<u8> {
        let status_text = match self.status {
            200 => "OK",
            201 => "Created",
            204 => "No Content",
            400 => "Bad Request",
            401 => "Unauthorized",
            403 => "Forbidden",
            404 => "Not Found",
            500 => "Internal Server Error",
            502 => "Bad Gateway",
            503 => "Service Unavailable",
            504 => "Gateway Timeout",
            _ => "Unknown",
        };

        let mut response = format!("HTTP/1.1 {} {}\r\n", self.status, status_text);

        // Add content-length header
        response.push_str(&format!("content-length: {}\r\n", self.body.len()));

        // Add other headers
        for (name, value) in &self.headers {
            response.push_str(&format!("{}: {}\r\n", name, value));
        }

        response.push_str("\r\n");

        let mut bytes = response.into_bytes();
        bytes.extend_from_slice(&self.body);
        bytes
    }
}

/// A mock HTTP server for integration testing.
///
/// `MockServer` spawns an actual TCP server on a random port, allowing you to
/// test HTTP client code against a real server. It records all incoming requests
/// and allows you to configure canned responses.
///
/// # Features
///
/// - **Real TCP server**: Listens on an actual port for real HTTP connections
/// - **Request recording**: Records all requests for later assertions
/// - **Canned responses**: Configure responses for specific paths
/// - **Clean shutdown**: Server shuts down when dropped
///
/// # Example
///
/// ```ignore
/// use fastapi_core::testing::{MockServer, MockResponse};
///
/// // Start a mock server
/// let server = MockServer::start();
///
/// // Configure a response
/// server.mock_response("/api/users", MockResponse::ok().json(&vec!["Alice", "Bob"]));
///
/// // Make requests with your HTTP client
/// let url = format!("http://{}/api/users", server.addr());
/// // ... make request ...
///
/// // Assert requests were made
/// let requests = server.requests();
/// assert_eq!(requests.len(), 1);
/// assert_eq!(requests[0].path, "/api/users");
/// ```
pub struct MockServer {
    addr: SocketAddr,
    requests: Arc<Mutex<Vec<RecordedRequest>>>,
    responses: Arc<Mutex<HashMap<String, MockResponse>>>,
    default_response: Arc<Mutex<MockResponse>>,
    shutdown: Arc<AtomicBool>,
    handle: Option<thread::JoinHandle<()>>,
}

impl MockServer {
    /// Starts a new mock server on a random available port.
    ///
    /// The server begins listening immediately and runs in a background thread.
    ///
    /// # Example
    ///
    /// ```ignore
    /// let server = MockServer::start();
    /// println!("Server listening on {}", server.addr());
    /// ```
    #[must_use]
    pub fn start() -> Self {
        Self::start_with_options(MockServerOptions::default())
    }

    /// Starts a mock server with custom options.
    #[must_use]
    pub fn start_with_options(options: MockServerOptions) -> Self {
        // Bind to a random port
        let listener =
            StdTcpListener::bind("127.0.0.1:0").expect("Failed to bind mock server to port");
        let addr = listener.local_addr().expect("Failed to get local address");

        // Set non-blocking for clean shutdown
        listener
            .set_nonblocking(true)
            .expect("Failed to set non-blocking");

        let requests = Arc::new(Mutex::new(Vec::new()));
        let responses = Arc::new(Mutex::new(HashMap::new()));
        let default_response = Arc::new(Mutex::new(options.default_response));
        let shutdown = Arc::new(AtomicBool::new(false));

        let requests_clone = Arc::clone(&requests);
        let responses_clone = Arc::clone(&responses);
        let default_response_clone = Arc::clone(&default_response);
        let shutdown_clone = Arc::clone(&shutdown);
        let read_timeout = options.read_timeout;

        let handle = thread::spawn(move || {
            Self::server_loop(
                listener,
                requests_clone,
                responses_clone,
                default_response_clone,
                shutdown_clone,
                read_timeout,
            );
        });

        Self {
            addr,
            requests,
            responses,
            default_response,
            shutdown,
            handle: Some(handle),
        }
    }

    /// The main server loop.
    fn server_loop(
        listener: StdTcpListener,
        requests: Arc<Mutex<Vec<RecordedRequest>>>,
        responses: Arc<Mutex<HashMap<String, MockResponse>>>,
        default_response: Arc<Mutex<MockResponse>>,
        shutdown: Arc<AtomicBool>,
        read_timeout: Duration,
    ) {
        loop {
            if shutdown.load(std::sync::atomic::Ordering::Acquire) {
                break;
            }

            match listener.accept() {
                Ok((stream, _peer)) => {
                    // Handle the connection
                    let requests = Arc::clone(&requests);
                    let responses = Arc::clone(&responses);
                    let default_response = Arc::clone(&default_response);

                    // Handle connection in the same thread (simple mock server)
                    Self::handle_connection(
                        stream,
                        requests,
                        responses,
                        default_response,
                        read_timeout,
                    );
                }
                Err(ref e) if e.kind() == std::io::ErrorKind::WouldBlock => {
                    // No connection available, sleep briefly and try again
                    thread::sleep(Duration::from_millis(10));
                }
                Err(e) => {
                    eprintln!("MockServer accept error: {}", e);
                    break;
                }
            }
        }
    }

    /// Handles a single connection.
    fn handle_connection(
        mut stream: StdTcpStream,
        requests: Arc<Mutex<Vec<RecordedRequest>>>,
        responses: Arc<Mutex<HashMap<String, MockResponse>>>,
        default_response: Arc<Mutex<MockResponse>>,
        read_timeout: Duration,
    ) {
        // Set read timeout
        let _ = stream.set_read_timeout(Some(read_timeout));

        // Read the request
        let mut buffer = vec![0u8; 8192];
        let Ok(bytes_read) = stream.read(&mut buffer) else {
            return;
        };

        if bytes_read == 0 {
            return;
        }

        buffer.truncate(bytes_read);

        // Parse the request
        let Some(recorded) = Self::parse_request(&buffer) else {
            return;
        };

        // Record the request
        {
            let mut reqs = requests.lock();
            reqs.push(recorded.clone());
        }

        // Find matching response
        let response = {
            let resps = responses.lock();
            match resps.get(&recorded.path) {
                Some(r) => r.clone(),
                None => {
                    // Check for pattern matches
                    let mut matched = None;
                    for (pattern, resp) in resps.iter() {
                        if pattern.ends_with('*') {
                            let prefix = &pattern[..pattern.len() - 1];
                            if recorded.path.starts_with(prefix) {
                                matched = Some(resp.clone());
                                break;
                            }
                        }
                    }
                    matched.unwrap_or_else(|| default_response.lock().clone())
                }
            }
        };

        // Apply delay if configured
        if let Some(delay) = response.delay {
            thread::sleep(delay);
        }

        // Send response
        let response_bytes = response.to_http_response();
        let _ = stream.write_all(&response_bytes);
        let _ = stream.flush();
    }

    /// Parses an HTTP request from raw bytes.
    fn parse_request(data: &[u8]) -> Option<RecordedRequest> {
        let text = std::str::from_utf8(data).ok()?;
        let mut lines = text.lines();

        // Parse request line
        let request_line = lines.next()?;
        let parts: Vec<&str> = request_line.split_whitespace().collect();
        if parts.len() < 2 {
            return None;
        }

        let method = parts[0].to_string();
        let full_path = parts[1];

        // Split path and query
        let (path, query) = if let Some(idx) = full_path.find('?') {
            (
                full_path[..idx].to_string(),
                Some(full_path[idx + 1..].to_string()),
            )
        } else {
            (full_path.to_string(), None)
        };

        // Parse headers
        let mut headers = Vec::new();
        let mut content_length = 0usize;
        for line in lines.by_ref() {
            if line.is_empty() {
                break;
            }
            if let Some((name, value)) = line.split_once(':') {
                let name = name.trim().to_string();
                let value = value.trim().to_string();
                if name.eq_ignore_ascii_case("content-length") {
                    content_length = value.parse().unwrap_or(0);
                }
                headers.push((name, value));
            }
        }

        // Parse body
        let body = if content_length > 0 {
            // Find the body start in the original data
            if let Some(body_start) = text.find("\r\n\r\n") {
                let body_start = body_start + 4;
                if body_start < data.len() {
                    data[body_start..].to_vec()
                } else {
                    Vec::new()
                }
            } else if let Some(body_start) = text.find("\n\n") {
                let body_start = body_start + 2;
                if body_start < data.len() {
                    data[body_start..].to_vec()
                } else {
                    Vec::new()
                }
            } else {
                Vec::new()
            }
        } else {
            Vec::new()
        };

        Some(RecordedRequest {
            method,
            path,
            query,
            headers,
            body,
            timestamp: std::time::Instant::now(),
        })
    }

    /// Returns the socket address the server is listening on.
    #[must_use]
    pub fn addr(&self) -> SocketAddr {
        self.addr
    }

    /// Returns the base URL for the server (e.g., "http://127.0.0.1:12345").
    #[must_use]
    pub fn url(&self) -> String {
        format!("http://{}", self.addr)
    }

    /// Returns a URL for the given path.
    #[must_use]
    pub fn url_for(&self, path: &str) -> String {
        let path = if path.starts_with('/') {
            path
        } else {
            &format!("/{}", path)
        };
        format!("http://{}{}", self.addr, path)
    }

    /// Configures a canned response for a specific path.
    ///
    /// Use `*` at the end of the path for prefix matching.
    ///
    /// # Example
    ///
    /// ```ignore
    /// server.mock_response("/api/users", MockResponse::ok().json(&users));
    /// server.mock_response("/api/*", MockResponse::with_status(404));
    /// ```
    pub fn mock_response(&self, path: impl Into<String>, response: MockResponse) {
        let mut responses = self.responses.lock();
        responses.insert(path.into(), response);
    }

    /// Sets the default response for unmatched paths.
    pub fn set_default_response(&self, response: MockResponse) {
        let mut default = self.default_response.lock();
        *default = response;
    }

    /// Returns all recorded requests.
    #[must_use]
    pub fn requests(&self) -> Vec<RecordedRequest> {
        let requests = self.requests.lock();
        requests.clone()
    }

    /// Returns the number of recorded requests.
    #[must_use]
    pub fn request_count(&self) -> usize {
        let requests = self.requests.lock();
        requests.len()
    }

    /// Returns requests matching the given path.
    #[must_use]
    pub fn requests_for(&self, path: &str) -> Vec<RecordedRequest> {
        let requests = self.requests.lock();
        requests
            .iter()
            .filter(|r| r.path == path)
            .cloned()
            .collect()
    }

    /// Returns the last recorded request.
    #[must_use]
    pub fn last_request(&self) -> Option<RecordedRequest> {
        let requests = self.requests.lock();
        requests.last().cloned()
    }

    /// Clears all recorded requests.
    pub fn clear_requests(&self) {
        let mut requests = self.requests.lock();
        requests.clear();
    }

    /// Clears all configured responses.
    pub fn clear_responses(&self) {
        let mut responses = self.responses.lock();
        responses.clear();
    }

    /// Resets the server (clears requests and responses).
    pub fn reset(&self) {
        self.clear_requests();
        self.clear_responses();
    }

    /// Waits for a specific number of requests, with timeout.
    ///
    /// Returns `true` if the expected number of requests were received,
    /// `false` if the timeout was reached.
    pub fn wait_for_requests(&self, count: usize, timeout: Duration) -> bool {
        let start = std::time::Instant::now();
        loop {
            if self.request_count() >= count {
                return true;
            }
            if start.elapsed() >= timeout {
                return false;
            }
            thread::sleep(Duration::from_millis(10));
        }
    }

    /// Asserts that a request was made to the given path.
    ///
    /// # Panics
    ///
    /// Panics if no request was made to the path.
    pub fn assert_received(&self, path: &str) {
        let requests = self.requests_for(path);
        assert!(
            !requests.is_empty(),
            "Expected request to path '{}', but none was received. Received paths: {:?}",
            path,
            self.requests().iter().map(|r| &r.path).collect::<Vec<_>>()
        );
    }

    /// Asserts that no request was made to the given path.
    ///
    /// # Panics
    ///
    /// Panics if a request was made to the path.
    pub fn assert_not_received(&self, path: &str) {
        let requests = self.requests_for(path);
        assert!(
            requests.is_empty(),
            "Expected no request to path '{}', but {} were received",
            path,
            requests.len()
        );
    }

    /// Asserts the total number of requests received.
    ///
    /// # Panics
    ///
    /// Panics if the count doesn't match.
    pub fn assert_request_count(&self, expected: usize) {
        let actual = self.request_count();
        assert_eq!(
            actual, expected,
            "Expected {} requests, but received {}",
            expected, actual
        );
    }
}

impl Drop for MockServer {
    fn drop(&mut self) {
        // Signal shutdown
        self.shutdown
            .store(true, std::sync::atomic::Ordering::Release);

        // Wait for the server thread to finish
        if let Some(handle) = self.handle.take() {
            let _ = handle.join();
        }
    }
}

/// Options for configuring a MockServer.
#[derive(Debug, Clone)]
pub struct MockServerOptions {
    /// Default response for unmatched paths.
    pub default_response: MockResponse,
    /// Read timeout for connections.
    pub read_timeout: Duration,
}

impl Default for MockServerOptions {
    fn default() -> Self {
        Self {
            default_response: MockResponse::with_status(404).body_str("Not Found"),
            read_timeout: Duration::from_secs(5),
        }
    }
}

impl MockServerOptions {
    /// Creates new options with default values.
    #[must_use]
    pub fn new() -> Self {
        Self::default()
    }

    /// Sets the default response.
    #[must_use]
    pub fn default_response(mut self, response: MockResponse) -> Self {
        self.default_response = response;
        self
    }

    /// Sets the read timeout.
    #[must_use]
    pub fn read_timeout(mut self, timeout: Duration) -> Self {
        self.read_timeout = timeout;
        self
    }
}

// =============================================================================
// Real HTTP Test Server
// =============================================================================

/// A log entry recorded by [`TestServer`] for each processed request.
///
/// This provides structured logging of all HTTP traffic flowing through
/// the test server, useful for debugging test failures.
#[derive(Debug, Clone)]
pub struct TestServerLogEntry {
    /// HTTP method (e.g., "GET", "POST").
    pub method: String,
    /// Request path (e.g., "/api/users").
    pub path: String,
    /// Response status code.
    pub status: u16,
    /// Time taken to process the request through the App pipeline.
    pub duration: Duration,
    /// When this request was received.
    pub timestamp: std::time::Instant,
}

/// Configuration for [`TestServer`].
#[derive(Debug, Clone)]
pub struct TestServerConfig {
    /// TCP read timeout for connections (default: 5 seconds).
    pub read_timeout: Duration,
    /// Whether to log each request/response (default: true).
    pub log_requests: bool,
}

impl Default for TestServerConfig {
    fn default() -> Self {
        Self {
            read_timeout: Duration::from_secs(5),
            log_requests: true,
        }
    }
}

impl TestServerConfig {
    /// Creates a new configuration with default values.
    #[must_use]
    pub fn new() -> Self {
        Self::default()
    }

    /// Sets the read timeout for TCP connections.
    #[must_use]
    pub fn read_timeout(mut self, timeout: Duration) -> Self {
        self.read_timeout = timeout;
        self
    }

    /// Sets whether to log requests.
    #[must_use]
    pub fn log_requests(mut self, log: bool) -> Self {
        self.log_requests = log;
        self
    }
}

/// A real HTTP test server that routes requests through the full App pipeline.
///
/// Unlike [`TestClient`] which operates in-process without network I/O,
/// `TestServer` creates actual TCP connections and processes requests through
/// the complete HTTP parsing -> App.handle() -> response serialization pipeline.
///
/// This enables true end-to-end testing including:
/// - HTTP request parsing from raw bytes
/// - Full middleware stack execution
/// - Route matching and handler dispatch
/// - Response serialization to HTTP/1.1
/// - Cookie handling over the wire
/// - Keep-alive and connection management
///
/// # Architecture
///
/// ```text
/// Test Code                        TestServer (background thread)
///     |                                 |
///     |-- TCP connect ----------------> |
///     |-- Send HTTP request ----------> |
///     |                                 |-- Parse HTTP request
///     |                                 |-- Create RequestContext
///     |                                 |-- App.handle(ctx, req)
///     |                                 |-- Serialize Response
///     |<-- Receive HTTP response ------ |
///     |                                 |-- Log entry recorded
/// ```
///
/// # Example
///
/// ```ignore
/// use fastapi_core::testing::TestServer;
/// use fastapi_core::app::App;
/// use std::io::{Read, Write};
/// use std::net::TcpStream;
///
/// let app = App::builder()
///     .get("/health", |_, _| async { Response::ok().body_text("OK") })
///     .build();
///
/// let server = TestServer::start(app);
/// println!("Server running on {}", server.url());
///
/// // Connect with any HTTP client
/// let mut stream = TcpStream::connect(server.addr()).unwrap();
/// stream.write_all(b"GET /health HTTP/1.1\r\nHost: localhost\r\n\r\n").unwrap();
///
/// let mut buf = vec![0u8; 4096];
/// let n = stream.read(&mut buf).unwrap();
/// let response = String::from_utf8_lossy(&buf[..n]);
/// assert!(response.contains("200 OK"));
///
/// // Check server logs
/// let logs = server.log_entries();
/// assert_eq!(logs.len(), 1);
/// assert_eq!(logs[0].path, "/health");
/// assert_eq!(logs[0].status, 200);
/// ```
pub struct TestServer {
    addr: SocketAddr,
    shutdown: Arc<AtomicBool>,
    handle: Option<thread::JoinHandle<()>>,
    log_entries: Arc<Mutex<Vec<TestServerLogEntry>>>,
    shutdown_controller: crate::shutdown::ShutdownController,
}

impl TestServer {
    /// Starts a new test server with the given App on a random available port.
    ///
    /// The server begins listening immediately and runs in a background thread.
    /// It will process requests through the full App pipeline including all
    /// middleware, routing, and error handling.
    ///
    /// # Panics
    ///
    /// Panics if binding to a local port fails.
    #[must_use]
    pub fn start(app: crate::app::App) -> Self {
        Self::start_with_config(app, TestServerConfig::default())
    }

    /// Starts a test server with custom configuration.
    #[must_use]
    pub fn start_with_config(app: crate::app::App, config: TestServerConfig) -> Self {
        let listener =
            StdTcpListener::bind("127.0.0.1:0").expect("Failed to bind test server to port");
        let addr = listener.local_addr().expect("Failed to get local address");

        listener
            .set_nonblocking(true)
            .expect("Failed to set non-blocking");

        let app = Arc::new(app);
        let shutdown = Arc::new(AtomicBool::new(false));
        let log_entries = Arc::new(Mutex::new(Vec::new()));
        let shutdown_controller = crate::shutdown::ShutdownController::new();

        let shutdown_clone = Arc::clone(&shutdown);
        let log_entries_clone = Arc::clone(&log_entries);
        let app_clone = Arc::clone(&app);
        let controller_clone = shutdown_controller.clone();

        let handle = thread::spawn(move || {
            Self::server_loop(
                listener,
                app_clone,
                shutdown_clone,
                log_entries_clone,
                config,
                controller_clone,
            );
        });

        Self {
            addr,
            shutdown,
            handle: Some(handle),
            log_entries,
            shutdown_controller,
        }
    }

    /// The main server loop — accepts connections and processes requests.
    fn server_loop(
        listener: StdTcpListener,
        app: Arc<crate::app::App>,
        shutdown: Arc<AtomicBool>,
        log_entries: Arc<Mutex<Vec<TestServerLogEntry>>>,
        config: TestServerConfig,
        controller: crate::shutdown::ShutdownController,
    ) {
        let request_counter = std::sync::atomic::AtomicU64::new(1);

        loop {
            if shutdown.load(std::sync::atomic::Ordering::Acquire) {
                // Run shutdown hooks before exiting
                while let Some(hook) = controller.pop_hook() {
                    hook.run();
                }
                break;
            }

            match listener.accept() {
                Ok((stream, _peer)) => {
                    // Track in-flight requests
                    let _guard = controller.track_request();

                    // If shutting down, reject with 503
                    if controller.is_shutting_down() {
                        Self::send_503(stream);
                        continue;
                    }

                    Self::handle_connection(stream, &app, &log_entries, &config, &request_counter);
                }
                Err(ref e) if e.kind() == std::io::ErrorKind::WouldBlock => {
                    thread::sleep(Duration::from_millis(5));
                }
                Err(_) => {
                    break;
                }
            }
        }
    }

    /// Handles a single TCP connection, potentially with keep-alive.
    fn handle_connection(
        mut stream: StdTcpStream,
        app: &Arc<crate::app::App>,
        log_entries: &Arc<Mutex<Vec<TestServerLogEntry>>>,
        config: &TestServerConfig,
        request_counter: &std::sync::atomic::AtomicU64,
    ) {
        let _ = stream.set_read_timeout(Some(config.read_timeout));

        // Read the request data
        let mut buffer = vec![0u8; 65536];
        let bytes_read = match stream.read(&mut buffer) {
            Ok(n) if n > 0 => n,
            _ => return,
        };
        buffer.truncate(bytes_read);

        // Parse the raw HTTP request into method, path, headers, body
        let Some(parsed) = Self::parse_raw_request(&buffer) else {
            // Send 400 Bad Request for unparseable requests
            let bad_request = b"HTTP/1.1 400 Bad Request\r\ncontent-length: 11\r\n\r\nBad Request";
            let _ = stream.write_all(bad_request);
            let _ = stream.flush();
            return;
        };

        let start_time = std::time::Instant::now();

        // Build a proper Request object
        let method = match parsed.method.to_uppercase().as_str() {
            "GET" => Method::Get,
            "POST" => Method::Post,
            "PUT" => Method::Put,
            "DELETE" => Method::Delete,
            "PATCH" => Method::Patch,
            "HEAD" => Method::Head,
            "OPTIONS" => Method::Options,
            _ => Method::Get,
        };

        let mut request = Request::new(method, &parsed.path);

        // Set query string if present
        if let Some(ref query) = parsed.query {
            request.set_query(Some(query.clone()));
        }

        // Copy headers
        for (name, value) in &parsed.headers {
            request
                .headers_mut()
                .insert(name.clone(), value.as_bytes().to_vec());
        }

        // Set body
        if !parsed.body.is_empty() {
            request.set_body(Body::Bytes(parsed.body.clone()));
        }

        // Create RequestContext with a Cx for testing
        let cx = Cx::for_testing();
        let request_id = request_counter.fetch_add(1, std::sync::atomic::Ordering::SeqCst);
        let dependency_overrides = Handler::dependency_overrides(app.as_ref())
            .unwrap_or_else(|| Arc::new(crate::dependency::DependencyOverrides::new()));
        let ctx = RequestContext::with_overrides(cx, request_id, dependency_overrides);

        // Execute the App handler synchronously
        let response = futures_executor::block_on(app.handle(&ctx, &mut request));

        let duration = start_time.elapsed();
        let status_code = response.status().as_u16();

        // Log the request if configured
        if config.log_requests {
            let entry = TestServerLogEntry {
                method: parsed.method.clone(),
                path: parsed.path.clone(),
                status: status_code,
                duration,
                timestamp: start_time,
            };
            log_entries.lock().push(entry);
        }

        // Serialize the Response to HTTP/1.1 bytes and send
        let response_bytes = Self::serialize_response(response);
        let _ = stream.write_all(&response_bytes);
        let _ = stream.flush();
    }

    /// Parses raw HTTP request bytes into structured components.
    fn parse_raw_request(data: &[u8]) -> Option<ParsedRequest> {
        let text = std::str::from_utf8(data).ok()?;
        let mut lines = text.lines();

        // Parse request line: "GET /path HTTP/1.1"
        let request_line = lines.next()?;
        let parts: Vec<&str> = request_line.split_whitespace().collect();
        if parts.len() < 2 {
            return None;
        }

        let method = parts[0].to_string();
        let full_path = parts[1];

        // Split path and query string
        let (path, query) = if let Some(idx) = full_path.find('?') {
            (
                full_path[..idx].to_string(),
                Some(full_path[idx + 1..].to_string()),
            )
        } else {
            (full_path.to_string(), None)
        };

        // Parse headers
        let mut headers = Vec::new();
        let mut content_length = 0usize;
        for line in lines.by_ref() {
            if line.is_empty() {
                break;
            }
            if let Some((name, value)) = line.split_once(':') {
                let name = name.trim().to_string();
                let value = value.trim().to_string();
                if name.eq_ignore_ascii_case("content-length") {
                    content_length = value.parse().unwrap_or(0);
                }
                headers.push((name, value));
            }
        }

        // Parse body
        let body = if content_length > 0 {
            if let Some(body_start) = text.find("\r\n\r\n") {
                let body_start = body_start + 4;
                if body_start < data.len() {
                    data[body_start..].to_vec()
                } else {
                    Vec::new()
                }
            } else if let Some(body_start) = text.find("\n\n") {
                let body_start = body_start + 2;
                if body_start < data.len() {
                    data[body_start..].to_vec()
                } else {
                    Vec::new()
                }
            } else {
                Vec::new()
            }
        } else {
            Vec::new()
        };

        Some(ParsedRequest {
            method,
            path,
            query,
            headers,
            body,
        })
    }

    /// Serializes a Response to HTTP/1.1 wire format bytes.
    fn serialize_response(response: Response) -> Vec<u8> {
        let (status, headers, body) = response.into_parts();

        let body_bytes = match body {
            ResponseBody::Empty => Vec::new(),
            ResponseBody::Bytes(b) => b,
            ResponseBody::Stream(_) => {
                // For streaming responses in test context, we can't easily
                // collect the stream synchronously. Return empty body.
                Vec::new()
            }
        };

        let mut buf = Vec::with_capacity(512 + body_bytes.len());

        // Status line
        buf.extend_from_slice(b"HTTP/1.1 ");
        buf.extend_from_slice(status.as_u16().to_string().as_bytes());
        buf.extend_from_slice(b" ");
        buf.extend_from_slice(status.canonical_reason().as_bytes());
        buf.extend_from_slice(b"\r\n");

        // Headers (skip content-length and transfer-encoding; we'll add our own)
        for (name, value) in &headers {
            if name.eq_ignore_ascii_case("content-length")
                || name.eq_ignore_ascii_case("transfer-encoding")
            {
                continue;
            }
            buf.extend_from_slice(name.as_bytes());
            buf.extend_from_slice(b": ");
            buf.extend_from_slice(value);
            buf.extend_from_slice(b"\r\n");
        }

        // Content-Length
        buf.extend_from_slice(b"content-length: ");
        buf.extend_from_slice(body_bytes.len().to_string().as_bytes());
        buf.extend_from_slice(b"\r\n");

        // End of headers
        buf.extend_from_slice(b"\r\n");

        // Body
        buf.extend_from_slice(&body_bytes);

        buf
    }

    /// Returns the socket address the server is listening on.
    #[must_use]
    pub fn addr(&self) -> SocketAddr {
        self.addr
    }

    /// Returns the port the server is listening on.
    #[must_use]
    pub fn port(&self) -> u16 {
        self.addr.port()
    }

    /// Returns the base URL (e.g., "http://127.0.0.1:12345").
    #[must_use]
    pub fn url(&self) -> String {
        format!("http://{}", self.addr)
    }

    /// Returns a URL for the given path.
    #[must_use]
    pub fn url_for(&self, path: &str) -> String {
        let path = if path.starts_with('/') {
            path.to_string()
        } else {
            format!("/{path}")
        };
        format!("http://{}{}", self.addr, path)
    }

    /// Returns a snapshot of all log entries recorded so far.
    #[must_use]
    pub fn log_entries(&self) -> Vec<TestServerLogEntry> {
        self.log_entries.lock().clone()
    }

    /// Returns the number of requests processed.
    #[must_use]
    pub fn request_count(&self) -> usize {
        self.log_entries.lock().len()
    }

    /// Clears all recorded log entries.
    pub fn clear_logs(&self) {
        self.log_entries.lock().clear();
    }

    /// Sends a 503 Service Unavailable response during shutdown.
    fn send_503(mut stream: StdTcpStream) {
        let response =
            b"HTTP/1.1 503 Service Unavailable\r\ncontent-length: 19\r\n\r\nService Unavailable";
        let _ = stream.write_all(response);
        let _ = stream.flush();
    }

    /// Returns a reference to the server's shutdown controller.
    ///
    /// Use this to coordinate graceful shutdown in tests, including:
    /// - Tracking in-flight requests via [`crate::ShutdownController::track_request`]
    /// - Registering shutdown hooks via [`crate::ShutdownController::register_hook`]
    /// - Checking shutdown phase via [`crate::ShutdownController::phase`]
    #[must_use]
    pub fn shutdown_controller(&self) -> &crate::shutdown::ShutdownController {
        &self.shutdown_controller
    }

    /// Returns the number of currently in-flight requests.
    #[must_use]
    pub fn in_flight_count(&self) -> usize {
        self.shutdown_controller.in_flight_count()
    }

    /// Signals the server to shut down gracefully.
    ///
    /// This triggers the shutdown controller (which will cause the server
    /// to reject new requests with 503) and stops the accept loop.
    /// This is also called automatically on drop.
    pub fn shutdown(&self) {
        self.shutdown_controller.shutdown();
        self.shutdown
            .store(true, std::sync::atomic::Ordering::Release);
    }

    /// Returns true if the server has been signaled to shut down.
    #[must_use]
    pub fn is_shutdown(&self) -> bool {
        self.shutdown.load(std::sync::atomic::Ordering::Acquire)
    }
}

impl Drop for TestServer {
    fn drop(&mut self) {
        self.shutdown
            .store(true, std::sync::atomic::Ordering::Release);
        if let Some(handle) = self.handle.take() {
            let _ = handle.join();
        }
    }
}

/// Internal parsed request for TestServer (not the same as Request).
struct ParsedRequest {
    method: String,
    path: String,
    query: Option<String>,
    headers: Vec<(String, String)>,
    body: Vec<u8>,
}

// =============================================================================
// E2E Testing Framework
// =============================================================================

/// Result of executing an E2E step.
#[derive(Debug, Clone)]
pub enum E2EStepResult {
    /// Step passed successfully.
    Passed,
    /// Step failed with an error message.
    Failed(String),
    /// Step was skipped (e.g., due to prior failure).
    Skipped,
}

impl E2EStepResult {
    /// Returns `true` if the step passed.
    #[must_use]
    pub fn is_passed(&self) -> bool {
        matches!(self, Self::Passed)
    }

    /// Returns `true` if the step failed.
    #[must_use]
    pub fn is_failed(&self) -> bool {
        matches!(self, Self::Failed(_))
    }
}

/// A captured HTTP request/response pair from an E2E step.
#[derive(Debug, Clone)]
pub struct E2ECapture {
    /// The request method.
    pub method: String,
    /// The request path.
    pub path: String,
    /// Request headers.
    pub request_headers: Vec<(String, String)>,
    /// Request body (if any).
    pub request_body: Option<String>,
    /// Response status code.
    pub response_status: u16,
    /// Response headers.
    pub response_headers: Vec<(String, String)>,
    /// Response body.
    pub response_body: String,
}

/// A single step in an E2E test scenario.
#[derive(Debug, Clone)]
pub struct E2EStep {
    /// Step name/description.
    pub name: String,
    /// When the step started.
    pub started_at: std::time::Instant,
    /// Step duration.
    pub duration: std::time::Duration,
    /// Step result.
    pub result: E2EStepResult,
    /// Captured request/response (if applicable).
    pub capture: Option<E2ECapture>,
}

impl E2EStep {
    /// Creates a new step record.
    fn new(name: impl Into<String>) -> Self {
        Self {
            name: name.into(),
            started_at: std::time::Instant::now(),
            duration: std::time::Duration::ZERO,
            result: E2EStepResult::Skipped,
            capture: None,
        }
    }

    /// Marks the step as complete with a result.
    fn complete(&mut self, result: E2EStepResult) {
        self.duration = self.started_at.elapsed();
        self.result = result;
    }
}

/// E2E test scenario builder and executor.
///
/// Provides structured E2E testing with step logging, timing, and detailed
/// failure reporting. Automatically captures request/response data on failures.
///
/// # Example
///
/// ```ignore
/// use fastapi_core::testing::{E2EScenario, TestClient};
///
/// let client = TestClient::new(app);
/// let mut scenario = E2EScenario::new("User Registration Flow", client);
///
/// scenario.step("Visit registration page", |client| {
///     let response = client.get("/register").send();
///     assert_eq!(response.status().as_u16(), 200);
/// });
///
/// scenario.step("Submit registration form", |client| {
///     let response = client
///         .post("/register")
///         .json(&serde_json::json!({"email": "test@example.com", "password": "secret123"}))
///         .send();
///     assert_eq!(response.status().as_u16(), 201);
/// });
///
/// // Generate report
/// let report = scenario.report();
/// println!("{}", report.to_text());
/// ```
pub struct E2EScenario<H> {
    /// Scenario name.
    name: String,
    /// Description of what this scenario tests.
    description: Option<String>,
    /// The test client.
    client: TestClient<H>,
    /// Recorded steps.
    steps: Vec<E2EStep>,
    /// Whether to stop on first failure.
    stop_on_failure: bool,
    /// Whether a failure has occurred.
    has_failure: bool,
    /// Captured output for logging.
    log_buffer: Vec<String>,
}

impl<H: Handler + 'static> E2EScenario<H> {
    /// Creates a new E2E scenario.
    pub fn new(name: impl Into<String>, client: TestClient<H>) -> Self {
        let name = name.into();
        Self {
            name,
            description: None,
            client,
            steps: Vec::new(),
            stop_on_failure: true,
            has_failure: false,
            log_buffer: Vec::new(),
        }
    }

    /// Sets the scenario description.
    #[must_use]
    pub fn description(mut self, desc: impl Into<String>) -> Self {
        self.description = Some(desc.into());
        self
    }

    /// Configures whether to stop on first failure (default: true).
    #[must_use]
    pub fn stop_on_failure(mut self, stop: bool) -> Self {
        self.stop_on_failure = stop;
        self
    }

    /// Returns a reference to the test client.
    pub fn client(&self) -> &TestClient<H> {
        &self.client
    }

    /// Returns a mutable reference to the test client.
    pub fn client_mut(&mut self) -> &mut TestClient<H> {
        &mut self.client
    }

    /// Logs a message to the scenario log.
    pub fn log(&mut self, message: impl Into<String>) {
        let msg = message.into();
        self.log_buffer.push(format!(
            "[{:?}] {}",
            std::time::Instant::now().elapsed(),
            msg
        ));
    }

    /// Executes a step in the scenario.
    ///
    /// The step function receives a reference to the test client and should
    /// perform assertions. Panics are caught and recorded as failures.
    pub fn step<F>(&mut self, name: impl Into<String>, f: F)
    where
        F: FnOnce(&TestClient<H>) + std::panic::UnwindSafe,
    {
        let name = name.into();
        let mut step = E2EStep::new(&name);

        // Skip if we've already failed and stop_on_failure is enabled
        if self.has_failure && self.stop_on_failure {
            step.complete(E2EStepResult::Skipped);
            self.log_buffer.push(format!("[SKIP] {}", name));
            self.steps.push(step);
            return;
        }

        self.log_buffer.push(format!("[START] {}", name));

        // Wrap client in AssertUnwindSafe for panic catching
        let client_ref = std::panic::AssertUnwindSafe(&self.client);

        // Execute the step and catch any panics
        let result = std::panic::catch_unwind(|| {
            f(&client_ref);
        });

        match result {
            Ok(()) => {
                step.complete(E2EStepResult::Passed);
                self.log_buffer
                    .push(format!("[PASS] {} ({:?})", name, step.duration));
            }
            Err(panic_info) => {
                let error_msg = if let Some(s) = panic_info.downcast_ref::<&str>() {
                    (*s).to_string()
                } else if let Some(s) = panic_info.downcast_ref::<String>() {
                    s.clone()
                } else {
                    "Unknown panic".to_string()
                };

                step.complete(E2EStepResult::Failed(error_msg.clone()));
                self.has_failure = true;
                self.log_buffer
                    .push(format!("[FAIL] {} - {}", name, error_msg));
            }
        }

        self.steps.push(step);
    }

    /// Executes a step that returns a result (for more control over error handling).
    pub fn try_step<F, E>(&mut self, name: impl Into<String>, f: F) -> Result<(), E>
    where
        F: FnOnce(&TestClient<H>) -> Result<(), E>,
        E: std::fmt::Display,
    {
        let name = name.into();
        let mut step = E2EStep::new(&name);

        if self.has_failure && self.stop_on_failure {
            step.complete(E2EStepResult::Skipped);
            self.steps.push(step);
            return Ok(());
        }

        self.log_buffer.push(format!("[START] {}", name));

        match f(&self.client) {
            Ok(()) => {
                step.complete(E2EStepResult::Passed);
                self.log_buffer
                    .push(format!("[PASS] {} ({:?})", name, step.duration));
                self.steps.push(step);
                Ok(())
            }
            Err(e) => {
                let error_msg = e.to_string();
                step.complete(E2EStepResult::Failed(error_msg.clone()));
                self.has_failure = true;
                self.log_buffer
                    .push(format!("[FAIL] {} - {}", name, error_msg));
                self.steps.push(step);
                Err(e)
            }
        }
    }

    /// Returns whether the scenario passed (no failures).
    #[must_use]
    pub fn passed(&self) -> bool {
        !self.has_failure
    }

    /// Returns the steps executed so far.
    #[must_use]
    pub fn steps(&self) -> &[E2EStep] {
        &self.steps
    }

    /// Returns the log buffer.
    #[must_use]
    pub fn logs(&self) -> &[String] {
        &self.log_buffer
    }

    /// Generates a test report.
    #[must_use]
    pub fn report(&self) -> E2EReport {
        let passed = self.steps.iter().filter(|s| s.result.is_passed()).count();
        let failed = self.steps.iter().filter(|s| s.result.is_failed()).count();
        let skipped = self
            .steps
            .iter()
            .filter(|s| matches!(s.result, E2EStepResult::Skipped))
            .count();
        let total_duration: std::time::Duration = self.steps.iter().map(|s| s.duration).sum();

        E2EReport {
            scenario_name: self.name.clone(),
            description: self.description.clone(),
            passed,
            failed,
            skipped,
            total_duration,
            steps: self.steps.clone(),
            logs: self.log_buffer.clone(),
        }
    }

    /// Asserts that the scenario passed, panicking with a detailed report if not.
    ///
    /// Call this at the end of your test to ensure all steps passed.
    pub fn assert_passed(&self) {
        if !self.passed() {
            let report = self.report();
            panic!(
                "E2E Scenario '{}' failed!\n\n{}",
                self.name,
                report.to_text()
            );
        }
    }
}

/// E2E test report with multiple output formats.
#[derive(Debug, Clone)]
pub struct E2EReport {
    /// Scenario name.
    pub scenario_name: String,
    /// Scenario description.
    pub description: Option<String>,
    /// Number of passed steps.
    pub passed: usize,
    /// Number of failed steps.
    pub failed: usize,
    /// Number of skipped steps.
    pub skipped: usize,
    /// Total duration.
    pub total_duration: std::time::Duration,
    /// Step details.
    pub steps: Vec<E2EStep>,
    /// Log messages.
    pub logs: Vec<String>,
}

impl E2EReport {
    /// Renders the report as plain text.
    #[must_use]
    pub fn to_text(&self) -> String {
        let mut output = String::new();

        // Header
        output.push_str(&format!("E2E Test Report: {}\n", self.scenario_name));
        output.push_str(&"=".repeat(60));
        output.push('\n');

        if let Some(desc) = &self.description {
            output.push_str(&format!("Description: {}\n", desc));
        }

        // Summary
        output.push_str(&format!(
            "\nSummary: {} passed, {} failed, {} skipped\n",
            self.passed, self.failed, self.skipped
        ));
        output.push_str(&format!("Total Duration: {:?}\n", self.total_duration));
        output.push_str(&"-".repeat(60));
        output.push('\n');

        // Steps
        output.push_str("\nSteps:\n");
        for (i, step) in self.steps.iter().enumerate() {
            let status = match &step.result {
                E2EStepResult::Passed => "[PASS]",
                E2EStepResult::Failed(_) => "[FAIL]",
                E2EStepResult::Skipped => "[SKIP]",
            };
            output.push_str(&format!(
                "  {}. {} {} ({:?})\n",
                i + 1,
                status,
                step.name,
                step.duration
            ));
            if let E2EStepResult::Failed(msg) = &step.result {
                output.push_str(&format!("     Error: {}\n", msg));
            }
        }

        // Logs
        if !self.logs.is_empty() {
            output.push_str(&"-".repeat(60));
            output.push_str("\n\nLogs:\n");
            for log in &self.logs {
                output.push_str(&format!("  {}\n", log));
            }
        }

        output
    }

    /// Renders the report as JSON.
    #[must_use]
    pub fn to_json(&self) -> String {
        let steps_json: Vec<String> = self
            .steps
            .iter()
            .map(|step| {
                let status = match &step.result {
                    E2EStepResult::Passed => "passed",
                    E2EStepResult::Failed(_) => "failed",
                    E2EStepResult::Skipped => "skipped",
                };
                let error = match &step.result {
                    E2EStepResult::Failed(msg) => format!(r#", "error": "{}""#, escape_json(msg)),
                    _ => String::new(),
                };
                format!(
                    r#"    {{ "name": "{}", "status": "{}", "duration_ms": {}{} }}"#,
                    escape_json(&step.name),
                    status,
                    step.duration.as_millis(),
                    error
                )
            })
            .collect();

        format!(
            r#"{{
  "scenario": "{}",
  "description": {},
  "summary": {{
    "passed": {},
    "failed": {},
    "skipped": {},
    "total_duration_ms": {}
  }},
  "steps": [
{}
  ]
}}"#,
            escape_json(&self.scenario_name),
            self.description
                .as_ref()
                .map_or("null".to_string(), |d| format!(r#""{}""#, escape_json(d))),
            self.passed,
            self.failed,
            self.skipped,
            self.total_duration.as_millis(),
            steps_json.join(",\n")
        )
    }

    /// Renders the report as HTML.
    #[must_use]
    pub fn to_html(&self) -> String {
        let status_class = if self.failed > 0 { "failed" } else { "passed" };

        use std::fmt::Write;
        let steps_html =
            self.steps
                .iter()
                .enumerate()
                .fold(String::new(), |mut output, (i, step)| {
                    let (status, class) = match &step.result {
                        E2EStepResult::Passed => ("✓", "pass"),
                        E2EStepResult::Failed(_) => ("✗", "fail"),
                        E2EStepResult::Skipped => ("○", "skip"),
                    };
                    let error_html = match &step.result {
                        E2EStepResult::Failed(msg) => {
                            format!(r#"<div class="error">{}</div>"#, escape_html(msg))
                        }
                        _ => String::new(),
                    };
                    let _ = write!(
                        output,
                        r#"    <tr class="{}">
      <td>{}</td>
      <td><span class="status">{}</span></td>
      <td>{}</td>
      <td>{:?}</td>
    </tr>
    {}"#,
                        class,
                        i + 1,
                        status,
                        escape_html(&step.name),
                        step.duration,
                        error_html
                    );
                    output
                });

        format!(
            r#"<!DOCTYPE html>
<html>
<head>
  <title>E2E Report: {}</title>
  <style>
    body {{ font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif; margin: 2rem; }}
    h1 {{ color: #333; }}
    .summary {{ padding: 1rem; border-radius: 8px; margin: 1rem 0; }}
    .summary.passed {{ background: #d4edda; }}
    .summary.failed {{ background: #f8d7da; }}
    table {{ width: 100%; border-collapse: collapse; margin-top: 1rem; }}
    th, td {{ padding: 0.75rem; text-align: left; border-bottom: 1px solid #dee2e6; }}
    th {{ background: #f8f9fa; }}
    .pass {{ color: #28a745; }}
    .fail {{ color: #dc3545; }}
    .skip {{ color: #6c757d; }}
    .status {{ font-size: 1.2rem; }}
    .error {{ color: #dc3545; font-size: 0.9rem; padding: 0.5rem; background: #fff; margin-top: 0.25rem; }}
  </style>
</head>
<body>
  <h1>E2E Report: {}</h1>
  {}
  <div class="summary {}">
    <strong>Summary:</strong> {} passed, {} failed, {} skipped<br>
    <strong>Duration:</strong> {:?}
  </div>
  <table>
    <thead>
      <tr><th>#</th><th>Status</th><th>Step</th><th>Duration</th></tr>
    </thead>
    <tbody>
{}
    </tbody>
  </table>
</body>
</html>"#,
            escape_html(&self.scenario_name),
            escape_html(&self.scenario_name),
            self.description
                .as_ref()
                .map_or(String::new(), |d| format!("<p>{}</p>", escape_html(d))),
            status_class,
            self.passed,
            self.failed,
            self.skipped,
            self.total_duration,
            steps_html
        )
    }
}

/// Helper function to escape JSON strings.
fn escape_json(s: &str) -> String {
    s.replace('\\', "\\\\")
        .replace('"', "\\\"")
        .replace('\n', "\\n")
        .replace('\r', "\\r")
        .replace('\t', "\\t")
}

/// Helper function to escape HTML.
fn escape_html(s: &str) -> String {
    s.replace('&', "&amp;")
        .replace('<', "&lt;")
        .replace('>', "&gt;")
        .replace('"', "&quot;")
}

/// Macro for defining E2E test scenarios with a declarative syntax.
///
/// # Example
///
/// ```ignore
/// use fastapi_core::testing::{e2e_test, TestClient};
///
/// e2e_test! {
///     name: "User Login Flow",
///     description: "Tests the complete user login process",
///     client: TestClient::new(app),
///
///     step "Navigate to login page" => |client| {
///         let response = client.get("/login").send();
///         assert_eq!(response.status().as_u16(), 200);
///     },
///
///     step "Submit credentials" => |client| {
///         let response = client
///             .post("/login")
///             .json(&serde_json::json!({"username": "test", "password": "secret"}))
///             .send();
///         assert_eq!(response.status().as_u16(), 302);
///     },
///
///     step "Access dashboard" => |client| {
///         let response = client.get("/dashboard").send();
///         assert_eq!(response.status().as_u16(), 200);
///         assert!(response.text().contains("Welcome"));
///     },
/// }
/// ```
#[macro_export]
macro_rules! e2e_test {
    (
        name: $name:expr,
        $(description: $desc:expr,)?
        client: $client:expr,
        $(step $step_name:literal => |$client_param:ident| $step_body:block),+ $(,)?
    ) => {{
        let client = $client;
        let mut scenario = $crate::testing::E2EScenario::new($name, client);
        $(
            scenario = scenario.description($desc);
        )?
        $(
            scenario.step($step_name, |$client_param| $step_body);
        )+
        scenario.assert_passed();
        scenario.report()
    }};
}

pub use e2e_test;

// =============================================================================
// Test Logging Utilities
// =============================================================================

use crate::logging::{LogEntry, LogLevel};

/// A captured log entry for test assertions.
#[derive(Debug, Clone)]
pub struct CapturedLog {
    /// The log level.
    pub level: LogLevel,
    /// The log message.
    pub message: String,
    /// Request ID associated with this log.
    pub request_id: u64,
    /// Timestamp when captured.
    pub captured_at: std::time::Instant,
    /// Structured fields as key-value pairs.
    pub fields: Vec<(String, String)>,
    /// Target module path (if any).
    pub target: Option<String>,
}

impl CapturedLog {
    /// Creates a new captured log from a LogEntry.
    pub fn from_entry(entry: &LogEntry) -> Self {
        Self {
            level: entry.level,
            message: entry.message.clone(),
            request_id: entry.request_id,
            captured_at: std::time::Instant::now(),
            fields: entry.fields.clone(),
            target: entry.target.clone(),
        }
    }

    /// Creates a captured log directly with specified values.
    pub fn new(level: LogLevel, message: impl Into<String>, request_id: u64) -> Self {
        Self {
            level,
            message: message.into(),
            request_id,
            captured_at: std::time::Instant::now(),
            fields: Vec::new(),
            target: None,
        }
    }

    /// Checks if the message contains the given substring.
    #[must_use]
    pub fn contains(&self, text: &str) -> bool {
        self.message.contains(text)
    }

    /// Formats for display in test output.
    #[must_use]
    pub fn format(&self) -> String {
        let mut output = format!(
            "[{}] req={} {}",
            self.level.as_char(),
            self.request_id,
            self.message
        );
        if !self.fields.is_empty() {
            output.push_str(" {");
            for (i, (k, v)) in self.fields.iter().enumerate() {
                if i > 0 {
                    output.push_str(", ");
                }
                output.push_str(&format!("{k}={v}"));
            }
            output.push('}');
        }
        output
    }
}

/// Test logger that captures logs for per-test isolation and assertions.
///
/// Use `TestLogger::capture` to run a test with isolated log capture,
/// then examine captured logs for assertions.
///
/// # Example
///
/// ```ignore
/// use fastapi_core::testing::TestLogger;
/// use fastapi_core::logging::LogLevel;
///
/// let capture = TestLogger::capture(|| {
///     let ctx = RequestContext::for_testing();
///     log_info!(ctx, "Hello from test");
///     log_debug!(ctx, "Debug info");
/// });
///
/// // Assert on captured logs
/// assert!(capture.contains_message("Hello from test"));
/// assert_eq!(capture.count_by_level(LogLevel::Info), 1);
///
/// // Get failure context (last N logs)
/// let context = capture.failure_context(5);
/// ```
#[derive(Debug, Clone)]
pub struct TestLogger {
    /// Captured log entries.
    logs: Arc<Mutex<Vec<CapturedLog>>>,
    /// Test phase timings.
    timings: Arc<Mutex<TestTimings>>,
    /// Whether to echo logs to stderr (for debugging).
    echo_logs: bool,
}

/// Timing breakdown for test phases.
#[derive(Debug, Clone, Default)]
pub struct TestTimings {
    /// Setup phase duration.
    pub setup: Option<std::time::Duration>,
    /// Execute phase duration.
    pub execute: Option<std::time::Duration>,
    /// Teardown phase duration.
    pub teardown: Option<std::time::Duration>,
    /// Phase start time.
    phase_start: Option<std::time::Instant>,
}

impl TestTimings {
    /// Starts timing a phase.
    pub fn start_phase(&mut self) {
        self.phase_start = Some(std::time::Instant::now());
    }

    /// Ends the setup phase.
    pub fn end_setup(&mut self) {
        if let Some(start) = self.phase_start.take() {
            self.setup = Some(start.elapsed());
        }
    }

    /// Ends the execute phase.
    pub fn end_execute(&mut self) {
        if let Some(start) = self.phase_start.take() {
            self.execute = Some(start.elapsed());
        }
    }

    /// Ends the teardown phase.
    pub fn end_teardown(&mut self) {
        if let Some(start) = self.phase_start.take() {
            self.teardown = Some(start.elapsed());
        }
    }

    /// Total test duration.
    #[must_use]
    pub fn total(&self) -> std::time::Duration {
        self.setup.unwrap_or_default()
            + self.execute.unwrap_or_default()
            + self.teardown.unwrap_or_default()
    }

    /// Formats timings for display.
    #[must_use]
    pub fn format(&self) -> String {
        format!(
            "Timings: setup={:?}, execute={:?}, teardown={:?}, total={:?}",
            self.setup.unwrap_or_default(),
            self.execute.unwrap_or_default(),
            self.teardown.unwrap_or_default(),
            self.total()
        )
    }
}

impl TestLogger {
    /// Creates a new test logger.
    pub fn new() -> Self {
        Self {
            logs: Arc::new(Mutex::new(Vec::new())),
            timings: Arc::new(Mutex::new(TestTimings::default())),
            echo_logs: std::env::var("FASTAPI_TEST_ECHO_LOGS").is_ok(),
        }
    }

    /// Creates a logger that echoes logs to stderr.
    pub fn with_echo() -> Self {
        let mut logger = Self::new();
        logger.echo_logs = true;
        logger
    }

    /// Captures a log entry.
    pub fn log(&self, entry: CapturedLog) {
        if self.echo_logs {
            eprintln!("[LOG] {}", entry.format());
        }
        self.logs.lock().push(entry);
    }

    /// Captures a log from a LogEntry.
    pub fn log_entry(&self, entry: &LogEntry) {
        self.log(CapturedLog::from_entry(entry));
    }

    /// Logs a message directly (convenience method).
    pub fn log_message(&self, level: LogLevel, message: impl Into<String>, request_id: u64) {
        self.log(CapturedLog::new(level, message, request_id));
    }

    /// Gets all captured logs.
    #[must_use]
    pub fn logs(&self) -> Vec<CapturedLog> {
        self.logs.lock().clone()
    }

    /// Gets the number of captured logs.
    #[must_use]
    pub fn count(&self) -> usize {
        self.logs.lock().len()
    }

    /// Clears all captured logs.
    pub fn clear(&self) {
        self.logs.lock().clear();
    }

    /// Checks if any log contains the given message substring.
    #[must_use]
    pub fn contains_message(&self, text: &str) -> bool {
        self.logs.lock().iter().any(|log| log.contains(text))
    }

    /// Counts logs by level.
    #[must_use]
    pub fn count_by_level(&self, level: LogLevel) -> usize {
        self.logs
            .lock()
            .iter()
            .filter(|log| log.level == level)
            .count()
    }

    /// Gets logs at a specific level.
    #[must_use]
    pub fn logs_at_level(&self, level: LogLevel) -> Vec<CapturedLog> {
        self.logs
            .lock()
            .iter()
            .filter(|log| log.level == level)
            .cloned()
            .collect()
    }

    /// Gets the last N logs for failure context.
    #[must_use]
    pub fn failure_context(&self, n: usize) -> String {
        let logs = self.logs.lock();
        let start = logs.len().saturating_sub(n);
        let recent: Vec<_> = logs[start..].iter().map(CapturedLog::format).collect();

        if recent.is_empty() {
            "No logs captured".to_string()
        } else {
            format!(
                "Last {} log(s) before failure:\n  {}",
                recent.len(),
                recent.join("\n  ")
            )
        }
    }

    /// Gets timing breakdown.
    #[must_use]
    pub fn timings(&self) -> TestTimings {
        self.timings.lock().clone()
    }

    /// Starts timing a phase.
    pub fn start_phase(&self) {
        self.timings.lock().start_phase();
    }

    /// Marks end of setup phase.
    pub fn end_setup(&self) {
        self.timings.lock().end_setup();
    }

    /// Marks end of execute phase.
    pub fn end_execute(&self) {
        self.timings.lock().end_execute();
    }

    /// Marks end of teardown phase.
    pub fn end_teardown(&self) {
        self.timings.lock().end_teardown();
    }

    /// Runs a closure with log capture, returning a LogCapture result.
    ///
    /// This is the primary API for isolated test logging.
    pub fn capture<F, T>(f: F) -> LogCapture<T>
    where
        F: FnOnce(&TestLogger) -> T,
    {
        let logger = TestLogger::new();

        logger.start_phase();
        let result = std::panic::catch_unwind(std::panic::AssertUnwindSafe(|| {
            logger.end_setup();
            logger.start_phase();
            let result = f(&logger);
            logger.end_execute();
            result
        }));

        let (ok_result, panic_info) = match result {
            Ok(v) => (Some(v), None),
            Err(p) => {
                let msg = if let Some(s) = p.downcast_ref::<&str>() {
                    (*s).to_string()
                } else if let Some(s) = p.downcast_ref::<String>() {
                    s.clone()
                } else {
                    "Unknown panic".to_string()
                };
                (None, Some(msg))
            }
        };

        LogCapture {
            logs: logger.logs(),
            timings: logger.timings(),
            result: ok_result,
            panic_info,
        }
    }

    /// Runs a test with setup, execute, and teardown phases.
    pub fn capture_phased<S, E, D, T>(setup: S, execute: E, teardown: D) -> LogCapture<T>
    where
        S: FnOnce(&TestLogger),
        E: FnOnce(&TestLogger) -> T,
        D: FnOnce(&TestLogger),
    {
        let logger = TestLogger::new();

        // Setup phase
        logger.start_phase();
        let setup_panic = std::panic::catch_unwind(std::panic::AssertUnwindSafe(|| {
            setup(&logger);
        }));
        logger.end_setup();

        if setup_panic.is_err() {
            return LogCapture {
                logs: logger.logs(),
                timings: logger.timings(),
                result: None,
                panic_info: Some("Setup phase panicked".to_string()),
            };
        }

        // Execute phase
        logger.start_phase();
        let result = std::panic::catch_unwind(std::panic::AssertUnwindSafe(|| execute(&logger)));
        logger.end_execute();

        // Teardown phase (always runs)
        logger.start_phase();
        let _ = std::panic::catch_unwind(std::panic::AssertUnwindSafe(|| {
            teardown(&logger);
        }));
        logger.end_teardown();

        let (ok_result, panic_info) = match result {
            Ok(v) => (Some(v), None),
            Err(p) => {
                let msg = if let Some(s) = p.downcast_ref::<&str>() {
                    (*s).to_string()
                } else if let Some(s) = p.downcast_ref::<String>() {
                    s.clone()
                } else {
                    "Unknown panic".to_string()
                };
                (None, Some(msg))
            }
        };

        LogCapture {
            logs: logger.logs(),
            timings: logger.timings(),
            result: ok_result,
            panic_info,
        }
    }
}

impl Default for TestLogger {
    fn default() -> Self {
        Self::new()
    }
}

/// Result of a log capture operation.
#[derive(Debug)]
pub struct LogCapture<T> {
    /// Captured log entries.
    pub logs: Vec<CapturedLog>,
    /// Phase timings.
    pub timings: TestTimings,
    /// Test result (if successful).
    pub result: Option<T>,
    /// Panic information (if failed).
    pub panic_info: Option<String>,
}

impl<T> LogCapture<T> {
    /// Returns `true` if the test passed.
    #[must_use]
    pub fn passed(&self) -> bool {
        self.result.is_some()
    }

    /// Returns `true` if the test failed.
    #[must_use]
    pub fn failed(&self) -> bool {
        self.panic_info.is_some()
    }

    /// Checks if any log contains the given message substring.
    #[must_use]
    pub fn contains_message(&self, text: &str) -> bool {
        self.logs.iter().any(|log| log.contains(text))
    }

    /// Counts logs by level.
    #[must_use]
    pub fn count_by_level(&self, level: LogLevel) -> usize {
        self.logs.iter().filter(|log| log.level == level).count()
    }

    /// Gets the last N logs for failure context.
    #[must_use]
    pub fn failure_context(&self, n: usize) -> String {
        let start = self.logs.len().saturating_sub(n);
        let recent: Vec<_> = self.logs[start..].iter().map(CapturedLog::format).collect();

        let mut output = String::new();

        if let Some(ref panic) = self.panic_info {
            output.push_str(&format!("Test failed: {}\n\n", panic));
        }

        output.push_str(&self.timings.format());
        output.push_str("\n\n");

        if recent.is_empty() {
            output.push_str("No logs captured");
        } else {
            output.push_str(&format!(
                "Last {} log(s) before failure:\n  {}",
                recent.len(),
                recent.join("\n  ")
            ));
        }

        output
    }

    /// Unwraps the result, panicking with failure context if it failed.
    pub fn unwrap(self) -> T {
        match self.result {
            Some(v) => v,
            None => panic!(
                "Test failed with log context:\n{}",
                self.failure_context(10)
            ),
        }
    }

    /// Gets the result or returns a default.
    pub fn unwrap_or(self, default: T) -> T {
        self.result.unwrap_or(default)
    }
}

/// Assertion helper that includes log context on failure.
///
/// Use this instead of `assert!` to automatically include recent logs in
/// the failure message.
#[macro_export]
macro_rules! assert_with_logs {
    ($logger:expr, $cond:expr) => {
        if !$cond {
            panic!(
                "Assertion failed: {}\n\n{}",
                stringify!($cond),
                $logger.failure_context(10)
            );
        }
    };
    ($logger:expr, $cond:expr, $($arg:tt)+) => {
        if !$cond {
            panic!(
                "Assertion failed: {}\n\n{}",
                format!($($arg)+),
                $logger.failure_context(10)
            );
        }
    };
}

/// Assertion helper that includes log context for equality checks.
#[macro_export]
macro_rules! assert_eq_with_logs {
    ($logger:expr, $left:expr, $right:expr) => {
        if $left != $right {
            panic!(
                "Assertion failed: {} == {}\n  left:  {:?}\n  right: {:?}\n\n{}",
                stringify!($left),
                stringify!($right),
                $left,
                $right,
                $logger.failure_context(10)
            );
        }
    };
    ($logger:expr, $left:expr, $right:expr, $($arg:tt)+) => {
        if $left != $right {
            panic!(
                "Assertion failed: {}\n  left:  {:?}\n  right: {:?}\n\n{}",
                format!($($arg)+),
                $left,
                $right,
                $logger.failure_context(10)
            );
        }
    };
}

pub use assert_eq_with_logs;
pub use assert_with_logs;

/// Request/response diff helper for test assertions.
#[derive(Debug)]
pub struct ResponseDiff {
    /// Expected status code.
    pub expected_status: u16,
    /// Actual status code.
    pub actual_status: u16,
    /// Expected body substring or full content.
    pub expected_body: Option<String>,
    /// Actual body content.
    pub actual_body: String,
    /// Header differences (name, expected, actual).
    pub header_diffs: Vec<(String, Option<String>, Option<String>)>,
}

impl ResponseDiff {
    /// Creates a new diff from expected and actual responses.
    pub fn new(expected_status: u16, actual: &TestResponse) -> Self {
        Self {
            expected_status,
            actual_status: actual.status().as_u16(),
            expected_body: None,
            actual_body: actual.text().to_string(),
            header_diffs: Vec::new(),
        }
    }

    /// Sets expected body for comparison.
    #[must_use]
    pub fn expected_body(mut self, body: impl Into<String>) -> Self {
        self.expected_body = Some(body.into());
        self
    }

    /// Adds an expected header.
    #[must_use]
    pub fn expected_header(mut self, name: impl Into<String>, value: impl Into<String>) -> Self {
        self.header_diffs
            .push((name.into(), Some(value.into()), None));
        self
    }

    /// Returns `true` if there are no differences.
    #[must_use]
    pub fn is_match(&self) -> bool {
        if self.expected_status != self.actual_status {
            return false;
        }
        if let Some(ref expected) = self.expected_body {
            if !self.actual_body.contains(expected) {
                return false;
            }
        }
        true
    }

    /// Formats the diff for display.
    #[must_use]
    pub fn format(&self) -> String {
        let mut output = String::new();

        if self.expected_status != self.actual_status {
            output.push_str(&format!(
                "Status mismatch:\n  expected: {}\n  actual:   {}\n",
                self.expected_status, self.actual_status
            ));
        }

        if let Some(ref expected) = self.expected_body {
            if !self.actual_body.contains(expected) {
                output.push_str(&format!(
                    "Body mismatch:\n  expected to contain: {:?}\n  actual: {:?}\n",
                    expected, self.actual_body
                ));
            }
        }

        for (name, expected, actual) in &self.header_diffs {
            output.push_str(&format!(
                "Header '{}' mismatch:\n  expected: {:?}\n  actual:   {:?}\n",
                name, expected, actual
            ));
        }

        if output.is_empty() {
            "No differences".to_string()
        } else {
            output
        }
    }
}

// ============================================================================
// Snapshot Testing Utilities
// ============================================================================

/// A serializable snapshot of an HTTP response for fixture-based testing.
///
/// Snapshots capture status code, selected headers, and body content,
/// enabling API contract verification by comparing responses against
/// stored fixtures.
///
/// # Usage
///
/// ```ignore
/// let response = client.get("/api/users").send();
/// let snapshot = ResponseSnapshot::from_test_response(&response);
///
/// // First run: save the snapshot
/// snapshot.save("tests/snapshots/get_users.json").unwrap();
///
/// // Subsequent runs: compare against saved snapshot
/// let expected = ResponseSnapshot::load("tests/snapshots/get_users.json").unwrap();
/// assert_eq!(snapshot, expected, "{}", snapshot.diff(&expected));
/// ```
#[derive(Debug, Clone, serde::Serialize, serde::Deserialize, PartialEq)]
pub struct ResponseSnapshot {
    /// HTTP status code.
    pub status: u16,
    /// Selected response headers (name, value) — sorted for determinism.
    pub headers: Vec<(String, String)>,
    /// Response body as a string.
    pub body: String,
    /// If the body is valid JSON, the parsed value for structural comparison.
    #[serde(skip_serializing_if = "Option::is_none")]
    pub body_json: Option<serde_json::Value>,
}

impl ResponseSnapshot {
    /// Create a snapshot from a `TestResponse`.
    ///
    /// Captures the status code, all response headers, and body text.
    /// If the body is valid JSON, it's also parsed for structural comparison.
    pub fn from_test_response(resp: &TestResponse) -> Self {
        let body = resp.text().to_string();
        let body_json = serde_json::from_str::<serde_json::Value>(&body).ok();

        let mut headers: Vec<(String, String)> = resp
            .headers()
            .iter()
            .filter_map(|(name, value)| {
                std::str::from_utf8(value)
                    .ok()
                    .map(|v| (name.to_lowercase(), v.to_string()))
            })
            .collect();
        headers.sort();

        Self {
            status: resp.status().as_u16(),
            headers,
            body,
            body_json,
        }
    }

    /// Create a snapshot with only specific headers (for ignoring dynamic headers).
    pub fn from_test_response_with_headers(resp: &TestResponse, header_names: &[&str]) -> Self {
        let mut snapshot = Self::from_test_response(resp);
        let names: Vec<String> = header_names.iter().map(|n| n.to_lowercase()).collect();
        snapshot.headers.retain(|(name, _)| names.contains(name));
        snapshot
    }

    /// Mask dynamic fields in the JSON body (replace with a placeholder).
    ///
    /// This is useful for fields like timestamps, UUIDs, or auto-increment IDs
    /// that change between test runs.
    ///
    /// `paths` are dot-separated JSON paths, e.g. `["id", "created_at", "items.0.id"]`.
    #[must_use]
    pub fn mask_fields(mut self, paths: &[&str], placeholder: &str) -> Self {
        if let Some(ref mut json) = self.body_json {
            for path in paths {
                mask_json_path(json, path, placeholder);
            }
            self.body = serde_json::to_string_pretty(json).unwrap_or(self.body);
        }
        self
    }

    /// Save the snapshot to a JSON file.
    pub fn save(&self, path: impl AsRef<std::path::Path>) -> std::io::Result<()> {
        let path = path.as_ref();
        if let Some(parent) = path.parent() {
            std::fs::create_dir_all(parent)?;
        }
        let json = serde_json::to_string_pretty(self).map_err(std::io::Error::other)?;
        std::fs::write(path, json)
    }

    /// Load a snapshot from a JSON file.
    pub fn load(path: impl AsRef<std::path::Path>) -> std::io::Result<Self> {
        let data = std::fs::read_to_string(path)?;
        serde_json::from_str(&data)
            .map_err(|e| std::io::Error::new(std::io::ErrorKind::InvalidData, e))
    }

    /// Compare two snapshots and return a human-readable diff.
    #[must_use]
    pub fn diff(&self, other: &Self) -> String {
        let mut output = String::new();

        if self.status != other.status {
            output.push_str(&format!("Status: {} vs {}\n", self.status, other.status));
        }

        // Header diffs
        for (name, value) in &self.headers {
            match other.headers.iter().find(|(n, _)| n == name) {
                Some((_, other_value)) if value != other_value => {
                    output.push_str(&format!(
                        "Header '{}': {:?} vs {:?}\n",
                        name, value, other_value
                    ));
                }
                None => {
                    output.push_str(&format!("Header '{}': present vs missing\n", name));
                }
                _ => {}
            }
        }
        for (name, _) in &other.headers {
            if !self.headers.iter().any(|(n, _)| n == name) {
                output.push_str(&format!("Header '{}': missing vs present\n", name));
            }
        }

        // Body diff
        if self.body != other.body {
            output.push_str(&format!(
                "Body:\n  expected: {:?}\n  actual:   {:?}\n",
                other.body, self.body
            ));
        }

        if output.is_empty() {
            "No differences".to_string()
        } else {
            output
        }
    }

    /// Check if two snapshots match, optionally ignoring specific headers.
    pub fn matches_ignoring_headers(&self, other: &Self, ignore: &[&str]) -> bool {
        if self.status != other.status {
            return false;
        }

        let ignore_lower: Vec<String> = ignore.iter().map(|s| s.to_lowercase()).collect();

        let self_headers: Vec<_> = self
            .headers
            .iter()
            .filter(|(n, _)| !ignore_lower.contains(n))
            .collect();
        let other_headers: Vec<_> = other
            .headers
            .iter()
            .filter(|(n, _)| !ignore_lower.contains(n))
            .collect();

        if self_headers != other_headers {
            return false;
        }

        // Compare JSON structurally if available, else compare strings
        match (&self.body_json, &other.body_json) {
            (Some(a), Some(b)) => a == b,
            _ => self.body == other.body,
        }
    }
}

/// Helper to mask a value at a dot-separated JSON path.
fn mask_json_path(value: &mut serde_json::Value, path: &str, placeholder: &str) {
    let parts: Vec<&str> = path.splitn(2, '.').collect();
    match parts.as_slice() {
        [key] => {
            if let Some(obj) = value.as_object_mut() {
                if obj.contains_key(*key) {
                    obj.insert(
                        key.to_string(),
                        serde_json::Value::String(placeholder.to_string()),
                    );
                }
            }
            if let Some(arr) = value.as_array_mut() {
                if let Ok(idx) = key.parse::<usize>() {
                    if idx < arr.len() {
                        arr[idx] = serde_json::Value::String(placeholder.to_string());
                    }
                }
            }
        }
        [key, rest] => {
            if let Some(obj) = value.as_object_mut() {
                if let Some(child) = obj.get_mut(*key) {
                    mask_json_path(child, rest, placeholder);
                }
            }
            if let Some(arr) = value.as_array_mut() {
                if let Ok(idx) = key.parse::<usize>() {
                    if let Some(child) = arr.get_mut(idx) {
                        mask_json_path(child, rest, placeholder);
                    }
                }
            }
        }
        _ => {}
    }
}

/// Macro for snapshot testing a response against a file fixture.
///
/// On first run (or when `SNAPSHOT_UPDATE=1`), saves the snapshot.
/// On subsequent runs, compares against the saved snapshot.
///
/// # Usage
///
/// ```ignore
/// let response = client.get("/api/users").send();
/// assert_response_snapshot!(response, "tests/snapshots/get_users.json");
///
/// // With field masking:
/// assert_response_snapshot!(response, "tests/snapshots/get_users.json", mask: ["id", "created_at"]);
/// ```
#[macro_export]
macro_rules! assert_response_snapshot {
    ($response:expr, $path:expr) => {{
        let snapshot = $crate::ResponseSnapshot::from_test_response(&$response);
        let path = std::path::Path::new($path);

        if std::env::var("SNAPSHOT_UPDATE").is_ok() || !path.exists() {
            snapshot.save(path).expect("failed to save snapshot");
        } else {
            let expected =
                $crate::ResponseSnapshot::load(path).expect("failed to load snapshot");
            assert!(
                snapshot == expected,
                "Snapshot mismatch for {}:\n{}",
                $path,
                snapshot.diff(&expected)
            );
        }
    }};
    ($response:expr, $path:expr, mask: [$($field:expr),* $(,)?]) => {{
        let snapshot = $crate::ResponseSnapshot::from_test_response(&$response)
            .mask_fields(&[$($field),*], "<MASKED>");
        let path = std::path::Path::new($path);

        if std::env::var("SNAPSHOT_UPDATE").is_ok() || !path.exists() {
            snapshot.save(path).expect("failed to save snapshot");
        } else {
            let expected =
                $crate::ResponseSnapshot::load(path).expect("failed to load snapshot");
            assert!(
                snapshot == expected,
                "Snapshot mismatch for {}:\n{}",
                $path,
                snapshot.diff(&expected)
            );
        }
    }};
}

#[cfg(test)]
mod snapshot_tests {
    use super::*;

    fn mock_test_response(status: u16, body: &str, headers: &[(&str, &str)]) -> TestResponse {
        let mut resp =
            crate::response::Response::with_status(crate::response::StatusCode::from_u16(status));
        for (name, value) in headers {
            resp = resp.header(*name, value.as_bytes().to_vec());
        }
        resp = resp.body(crate::response::ResponseBody::Bytes(
            body.as_bytes().to_vec(),
        ));
        TestResponse::new(resp, 0)
    }

    #[test]
    fn snapshot_from_test_response() {
        let resp = mock_test_response(
            200,
            r#"{"id":1,"name":"Alice"}"#,
            &[("content-type", "application/json")],
        );
        let snap = ResponseSnapshot::from_test_response(&resp);

        assert_eq!(snap.status, 200);
        assert!(snap.body_json.is_some());
        assert_eq!(snap.body_json.as_ref().unwrap()["name"], "Alice");
    }

    #[test]
    fn snapshot_equality() {
        let resp = mock_test_response(200, "hello", &[]);
        let snap1 = ResponseSnapshot::from_test_response(&resp);
        let snap2 = ResponseSnapshot::from_test_response(&resp);
        assert_eq!(snap1, snap2);
    }

    #[test]
    fn snapshot_diff_status() {
        let s1 = ResponseSnapshot {
            status: 200,
            headers: vec![],
            body: "ok".to_string(),
            body_json: None,
        };
        let s2 = ResponseSnapshot {
            status: 404,
            ..s1.clone()
        };
        let diff = s1.diff(&s2);
        assert!(diff.contains("200 vs 404"));
    }

    #[test]
    fn snapshot_diff_body() {
        let s1 = ResponseSnapshot {
            status: 200,
            headers: vec![],
            body: "hello".to_string(),
            body_json: None,
        };
        let s2 = ResponseSnapshot {
            body: "world".to_string(),
            ..s1.clone()
        };
        let diff = s1.diff(&s2);
        assert!(diff.contains("Body:"));
    }

    #[test]
    fn snapshot_diff_no_differences() {
        let s = ResponseSnapshot {
            status: 200,
            headers: vec![],
            body: "ok".to_string(),
            body_json: None,
        };
        assert_eq!(s.diff(&s), "No differences");
    }

    #[test]
    fn snapshot_mask_fields() {
        let resp = mock_test_response(
            200,
            r#"{"id":42,"name":"Alice","created_at":"2026-01-01"}"#,
            &[],
        );
        let snap = ResponseSnapshot::from_test_response(&resp)
            .mask_fields(&["id", "created_at"], "<MASKED>");

        let json = snap.body_json.unwrap();
        assert_eq!(json["id"], "<MASKED>");
        assert_eq!(json["name"], "Alice");
        assert_eq!(json["created_at"], "<MASKED>");
    }

    #[test]
    fn snapshot_mask_nested_fields() {
        let resp = mock_test_response(200, r#"{"user":{"id":1,"name":"Bob"}}"#, &[]);
        let snap =
            ResponseSnapshot::from_test_response(&resp).mask_fields(&["user.id"], "<MASKED>");

        let json = snap.body_json.unwrap();
        assert_eq!(json["user"]["id"], "<MASKED>");
        assert_eq!(json["user"]["name"], "Bob");
    }

    #[test]
    fn snapshot_save_and_load() {
        let snap = ResponseSnapshot {
            status: 200,
            headers: vec![("content-type".to_string(), "application/json".to_string())],
            body: r#"{"ok":true}"#.to_string(),
            body_json: Some(serde_json::json!({"ok": true})),
        };

        let dir = std::env::temp_dir().join("fastapi_snapshot_test");
        let path = dir.join("test_snap.json");
        snap.save(&path).unwrap();

        let loaded = ResponseSnapshot::load(&path).unwrap();
        assert_eq!(snap, loaded);

        // Cleanup
        let _ = std::fs::remove_dir_all(&dir);
    }

    #[test]
    fn snapshot_matches_ignoring_headers() {
        let s1 = ResponseSnapshot {
            status: 200,
            headers: vec![
                ("content-type".to_string(), "application/json".to_string()),
                ("x-request-id".to_string(), "abc".to_string()),
            ],
            body: "ok".to_string(),
            body_json: None,
        };
        let s2 = ResponseSnapshot {
            headers: vec![
                ("content-type".to_string(), "application/json".to_string()),
                ("x-request-id".to_string(), "xyz".to_string()),
            ],
            ..s1.clone()
        };

        assert!(!s1.matches_ignoring_headers(&s2, &[]));
        assert!(s1.matches_ignoring_headers(&s2, &["X-Request-Id"]));
    }

    #[test]
    fn snapshot_with_selected_headers() {
        let resp = mock_test_response(
            200,
            "ok",
            &[
                ("content-type", "text/plain"),
                ("x-request-id", "abc123"),
                ("x-trace-id", "trace-456"),
            ],
        );
        let snap = ResponseSnapshot::from_test_response_with_headers(&resp, &["content-type"]);

        assert_eq!(snap.headers.len(), 1);
        assert_eq!(snap.headers[0].0, "content-type");
    }

    #[test]
    fn snapshot_json_structural_comparison() {
        // Same JSON, different key order
        let s1 = ResponseSnapshot {
            status: 200,
            headers: vec![],
            body: r#"{"a":1,"b":2}"#.to_string(),
            body_json: Some(serde_json::json!({"a": 1, "b": 2})),
        };
        let s2 = ResponseSnapshot {
            body: r#"{"b":2,"a":1}"#.to_string(),
            body_json: Some(serde_json::json!({"b": 2, "a": 1})),
            ..s1.clone()
        };

        // PartialEq compares body strings too, so they differ
        assert_ne!(s1, s2);
        // But matches_ignoring_headers uses JSON structural comparison
        assert!(s1.matches_ignoring_headers(&s2, &[]));
    }
}

#[cfg(test)]
mod mock_server_tests {
    use super::*;

    #[test]
    fn mock_server_starts_and_responds() {
        let server = MockServer::start();
        server.mock_response("/hello", MockResponse::ok().body_str("Hello, World!"));

        // Make a simple HTTP request
        let mut stream = StdTcpStream::connect(server.addr()).expect("Failed to connect");
        stream
            .write_all(b"GET /hello HTTP/1.1\r\nHost: localhost\r\n\r\n")
            .unwrap();

        let mut response = String::new();
        stream.read_to_string(&mut response).unwrap();

        assert!(response.contains("200 OK"));
        assert!(response.contains("Hello, World!"));
    }

    #[test]
    fn mock_server_records_requests() {
        let server = MockServer::start();

        // Make a request
        let mut stream = StdTcpStream::connect(server.addr()).expect("Failed to connect");
        stream
            .write_all(b"GET /api/users HTTP/1.1\r\nHost: localhost\r\nX-Custom: value\r\n\r\n")
            .unwrap();
        let mut response = Vec::new();
        let _ = stream.read_to_end(&mut response);

        // Give the server time to process
        thread::sleep(Duration::from_millis(50));

        let requests = server.requests();
        assert_eq!(requests.len(), 1);
        assert_eq!(requests[0].method, "GET");
        assert_eq!(requests[0].path, "/api/users");
        assert_eq!(requests[0].header("x-custom"), Some("value"));
    }

    #[test]
    fn mock_server_handles_post_with_body() {
        let server = MockServer::start();
        server.mock_response(
            "/api/create",
            MockResponse::with_status(201).body_str("Created"),
        );

        let body = r#"{"name":"test"}"#;
        let request = format!(
            "POST /api/create HTTP/1.1\r\nHost: localhost\r\nContent-Length: {}\r\nContent-Type: application/json\r\n\r\n{}",
            body.len(),
            body
        );

        let mut stream = StdTcpStream::connect(server.addr()).expect("Failed to connect");
        stream.write_all(request.as_bytes()).unwrap();
        let mut response = String::new();
        stream.read_to_string(&mut response).unwrap();

        assert!(response.contains("201 Created"));

        thread::sleep(Duration::from_millis(50));
        let requests = server.requests();
        assert_eq!(requests.len(), 1);
        assert_eq!(requests[0].method, "POST");
        assert_eq!(requests[0].body_text(), body);
    }

    #[test]
    fn mock_server_pattern_matching() {
        let server = MockServer::start();
        server.mock_response("/api/*", MockResponse::ok().body_str("API Response"));

        let mut stream = StdTcpStream::connect(server.addr()).expect("Failed to connect");
        stream
            .write_all(b"GET /api/users/123 HTTP/1.1\r\nHost: localhost\r\n\r\n")
            .unwrap();
        let mut response = String::new();
        stream.read_to_string(&mut response).unwrap();

        assert!(response.contains("API Response"));
    }

    #[test]
    fn mock_server_default_response() {
        let server = MockServer::start();

        let mut stream = StdTcpStream::connect(server.addr()).expect("Failed to connect");
        stream
            .write_all(b"GET /unknown HTTP/1.1\r\nHost: localhost\r\n\r\n")
            .unwrap();
        let mut response = String::new();
        stream.read_to_string(&mut response).unwrap();

        assert!(response.contains("404"));
    }

    #[test]
    fn mock_server_url_helpers() {
        let server = MockServer::start();

        let url = server.url();
        assert!(url.starts_with("http://127.0.0.1:"));

        let api_url = server.url_for("/api/users");
        assert!(api_url.contains("/api/users"));
    }

    #[test]
    fn mock_server_clear_requests() {
        let server = MockServer::start();

        // Make a request
        let mut stream = StdTcpStream::connect(server.addr()).expect("Failed to connect");
        stream
            .write_all(b"GET /test HTTP/1.1\r\nHost: localhost\r\n\r\n")
            .unwrap();
        let mut response = Vec::new();
        let _ = stream.read_to_end(&mut response);

        thread::sleep(Duration::from_millis(50));
        assert_eq!(server.request_count(), 1);

        server.clear_requests();
        assert_eq!(server.request_count(), 0);
    }

    #[test]
    fn mock_server_wait_for_requests() {
        let server = MockServer::start();

        // Spawn a thread that will make a request after a delay
        let addr = server.addr();
        thread::spawn(move || {
            thread::sleep(Duration::from_millis(50));
            let mut stream = StdTcpStream::connect(addr).expect("Failed to connect");
            stream
                .write_all(b"GET /delayed HTTP/1.1\r\nHost: localhost\r\n\r\n")
                .unwrap();
        });

        let received = server.wait_for_requests(1, Duration::from_millis(500));
        assert!(received);
        assert_eq!(server.request_count(), 1);
    }

    #[test]
    fn mock_server_assert_helpers() {
        let server = MockServer::start();

        let mut stream = StdTcpStream::connect(server.addr()).expect("Failed to connect");
        stream
            .write_all(b"GET /expected HTTP/1.1\r\nHost: localhost\r\n\r\n")
            .unwrap();
        let mut response = Vec::new();
        let _ = stream.read_to_end(&mut response);

        thread::sleep(Duration::from_millis(50));

        server.assert_received("/expected");
        server.assert_not_received("/not-expected");
        server.assert_request_count(1);
    }

    #[test]
    fn mock_server_query_string_parsing() {
        let server = MockServer::start();

        let mut stream = StdTcpStream::connect(server.addr()).expect("Failed to connect");
        stream
            .write_all(b"GET /search?q=rust&limit=10 HTTP/1.1\r\nHost: localhost\r\n\r\n")
            .unwrap();
        let mut response = Vec::new();
        let _ = stream.read_to_end(&mut response);

        thread::sleep(Duration::from_millis(50));

        let requests = server.requests();
        assert_eq!(requests.len(), 1);
        assert_eq!(requests[0].path, "/search");
        assert_eq!(requests[0].query, Some("q=rust&limit=10".to_string()));
        assert_eq!(requests[0].url(), "/search?q=rust&limit=10");
    }

    #[test]
    fn mock_response_json() {
        #[derive(serde::Serialize)]
        struct User {
            name: String,
        }

        let response = MockResponse::ok().json(&User {
            name: "Alice".to_string(),
        });
        let bytes = response.to_http_response();
        let http = String::from_utf8_lossy(&bytes);

        assert!(http.contains("application/json"));
        assert!(http.contains("Alice"));
    }

    #[test]
    fn recorded_request_helpers() {
        let request = RecordedRequest {
            method: "GET".to_string(),
            path: "/api/users".to_string(),
            query: Some("page=1".to_string()),
            headers: vec![("Content-Type".to_string(), "application/json".to_string())],
            body: b"test body".to_vec(),
            timestamp: std::time::Instant::now(),
        };

        assert_eq!(request.body_text(), "test body");
        assert_eq!(request.header("content-type"), Some("application/json"));
        assert_eq!(request.url(), "/api/users?page=1");
    }
}

#[cfg(test)]
mod e2e_tests {
    use super::*;

    // Create a simple test handler for E2E testing
    fn test_handler(_ctx: &RequestContext, req: &mut Request) -> std::future::Ready<Response> {
        let path = req.path();
        let response = match path {
            "/" => Response::ok().body(ResponseBody::Bytes(b"Home".to_vec())),
            "/login" => Response::ok().body(ResponseBody::Bytes(b"Login Page".to_vec())),
            "/dashboard" => Response::ok().body(ResponseBody::Bytes(b"Dashboard".to_vec())),
            "/api/users" => {
                Response::ok().body(ResponseBody::Bytes(b"[\"Alice\",\"Bob\"]".to_vec()))
            }
            "/fail" => Response::with_status(StatusCode::INTERNAL_SERVER_ERROR)
                .body(ResponseBody::Bytes(b"Error".to_vec())),
            _ => Response::with_status(StatusCode::NOT_FOUND)
                .body(ResponseBody::Bytes(b"Not Found".to_vec())),
        };
        std::future::ready(response)
    }

    #[test]
    fn e2e_scenario_all_steps_pass() {
        let client = TestClient::new(test_handler);
        let mut scenario = E2EScenario::new("Basic Navigation", client);

        scenario.step("Visit home page", |client| {
            let response = client.get("/").send();
            assert_eq!(response.status().as_u16(), 200);
            assert_eq!(response.text(), "Home");
        });

        scenario.step("Visit login page", |client| {
            let response = client.get("/login").send();
            assert_eq!(response.status().as_u16(), 200);
        });

        assert!(scenario.passed());
        assert_eq!(scenario.steps().len(), 2);
        assert!(scenario.steps().iter().all(|s| s.result.is_passed()));
    }

    #[test]
    fn e2e_scenario_step_failure() {
        let client = TestClient::new(test_handler);
        let mut scenario = E2EScenario::new("Failure Test", client).stop_on_failure(true);

        scenario.step("First step passes", |client| {
            let response = client.get("/").send();
            assert_eq!(response.status().as_u16(), 200);
        });

        scenario.step("Second step fails", |_client| {
            panic!("Intentional failure");
        });

        scenario.step("Third step skipped", |client| {
            let response = client.get("/dashboard").send();
            assert_eq!(response.status().as_u16(), 200);
        });

        assert!(!scenario.passed());
        assert_eq!(scenario.steps().len(), 3);
        assert!(scenario.steps()[0].result.is_passed());
        assert!(scenario.steps()[1].result.is_failed());
        assert!(matches!(scenario.steps()[2].result, E2EStepResult::Skipped));
    }

    #[test]
    fn e2e_scenario_continue_on_failure() {
        let client = TestClient::new(test_handler);
        let mut scenario = E2EScenario::new("Continue Test", client).stop_on_failure(false);

        scenario.step("First step fails", |_client| {
            panic!("First failure");
        });

        scenario.step("Second step still runs", |client| {
            let response = client.get("/").send();
            assert_eq!(response.status().as_u16(), 200);
        });

        assert!(!scenario.passed());
        assert_eq!(scenario.steps().len(), 2);
        assert!(scenario.steps()[0].result.is_failed());
        // Second step ran (not skipped) and passed
        assert!(scenario.steps()[1].result.is_passed());
    }

    #[test]
    fn e2e_report_text_format() {
        let client = TestClient::new(test_handler);
        let mut scenario =
            E2EScenario::new("Report Test", client).description("Tests report generation");

        scenario.step("Step 1", |client| {
            let _ = client.get("/").send();
        });

        let report = scenario.report();
        let text = report.to_text();

        assert!(text.contains("E2E Test Report: Report Test"));
        assert!(text.contains("Tests report generation"));
        assert!(text.contains("1 passed"));
        assert!(text.contains("Step 1"));
    }

    #[test]
    fn e2e_report_json_format() {
        let client = TestClient::new(test_handler);
        let mut scenario = E2EScenario::new("JSON Test", client);

        scenario.step("API call", |client| {
            let response = client.get("/api/users").send();
            assert_eq!(response.status().as_u16(), 200);
        });

        let report = scenario.report();
        let json = report.to_json();

        assert!(json.contains(r#""scenario": "JSON Test""#));
        assert!(json.contains(r#""passed": 1"#));
        assert!(json.contains(r#""name": "API call""#));
        assert!(json.contains(r#""status": "passed""#));
    }

    #[test]
    fn e2e_report_html_format() {
        let client = TestClient::new(test_handler);
        let mut scenario = E2EScenario::new("HTML Test", client);

        scenario.step("Web visit", |client| {
            let _ = client.get("/").send();
        });

        let report = scenario.report();
        let html = report.to_html();

        assert!(html.contains("<!DOCTYPE html>"));
        assert!(html.contains("E2E Report: HTML Test"));
        assert!(html.contains("1 passed"));
        assert!(html.contains("Web visit"));
    }

    #[test]
    fn e2e_step_timing() {
        let client = TestClient::new(test_handler);
        let mut scenario = E2EScenario::new("Timing Test", client);

        scenario.step("Timed step", |_client| {
            // Small delay to ensure measurable duration
            std::thread::sleep(std::time::Duration::from_millis(10));
        });

        assert!(scenario.steps()[0].duration >= std::time::Duration::from_millis(10));
    }

    #[test]
    fn e2e_logs_captured() {
        let client = TestClient::new(test_handler);
        let mut scenario = E2EScenario::new("Log Test", client);

        scenario.log("Manual log entry");
        scenario.step("Logged step", |_client| {});

        assert!(
            scenario
                .logs()
                .iter()
                .any(|l| l.contains("Manual log entry"))
        );
        assert!(
            scenario
                .logs()
                .iter()
                .any(|l| l.contains("[START] Logged step"))
        );
        assert!(
            scenario
                .logs()
                .iter()
                .any(|l| l.contains("[PASS] Logged step"))
        );
    }

    #[test]
    fn e2e_try_step_with_result() {
        let client = TestClient::new(test_handler);
        let mut scenario = E2EScenario::new("Try Step Test", client);

        let result: Result<(), &str> = scenario.try_step("Success step", |client| {
            let response = client.get("/").send();
            if response.status().as_u16() == 200 {
                Ok(())
            } else {
                Err("Unexpected status")
            }
        });

        assert!(result.is_ok());
        assert!(scenario.passed());
    }

    #[test]
    fn e2e_escape_functions() {
        // Test JSON escaping
        assert_eq!(escape_json("hello"), "hello");
        assert_eq!(escape_json("a\"b"), "a\\\"b");
        assert_eq!(escape_json("a\nb"), "a\\nb");

        // Test HTML escaping
        assert_eq!(escape_html("hello"), "hello");
        assert_eq!(escape_html("<script>"), "&lt;script&gt;");
        assert_eq!(escape_html("a&b"), "a&amp;b");
    }

    #[test]
    fn e2e_step_result_helpers() {
        let passed = E2EStepResult::Passed;
        let failed = E2EStepResult::Failed("error".to_string());
        let skipped = E2EStepResult::Skipped;

        assert!(passed.is_passed());
        assert!(!passed.is_failed());

        assert!(!failed.is_passed());
        assert!(failed.is_failed());

        assert!(!skipped.is_passed());
        assert!(!skipped.is_failed());
    }
}

// =============================================================================
// Integration Test Framework
// =============================================================================

/// Trait for test fixtures that set up and tear down test data.
///
/// Implement this trait for resources that need initialization before tests
/// and cleanup afterwards (databases, temp files, mock services, etc.).
///
/// # Example
///
/// ```ignore
/// use fastapi_core::testing::TestFixture;
///
/// struct DatabaseFixture {
///     conn: DatabaseConnection,
///     users_created: Vec<i64>,
/// }
///
/// impl TestFixture for DatabaseFixture {
///     fn setup() -> Self {
///         let conn = DatabaseConnection::test();
///         DatabaseFixture { conn, users_created: vec![] }
///     }
///
///     fn teardown(&mut self) {
///         // Delete any users we created
///         for id in &self.users_created {
///             self.conn.delete_user(*id);
///         }
///     }
/// }
/// ```
pub trait TestFixture: Sized + Send {
    /// Set up the fixture before the test.
    fn setup() -> Self;

    /// Tear down the fixture after the test.
    ///
    /// This is called even if the test panics, ensuring cleanup happens.
    fn teardown(&mut self) {}
}

/// A guard that automatically calls teardown when dropped.
///
/// This ensures fixtures are cleaned up even if the test panics.
pub struct FixtureGuard<F: TestFixture> {
    fixture: Option<F>,
}

impl<F: TestFixture> FixtureGuard<F> {
    /// Creates a new fixture guard, setting up the fixture.
    pub fn new() -> Self {
        Self {
            fixture: Some(F::setup()),
        }
    }

    /// Get a reference to the fixture.
    pub fn get(&self) -> &F {
        self.fixture.as_ref().unwrap()
    }

    /// Get a mutable reference to the fixture.
    pub fn get_mut(&mut self) -> &mut F {
        self.fixture.as_mut().unwrap()
    }
}

impl<F: TestFixture> Default for FixtureGuard<F> {
    fn default() -> Self {
        Self::new()
    }
}

impl<F: TestFixture> Drop for FixtureGuard<F> {
    fn drop(&mut self) {
        if let Some(mut fixture) = self.fixture.take() {
            fixture.teardown();
        }
    }
}

impl<F: TestFixture> std::ops::Deref for FixtureGuard<F> {
    type Target = F;

    fn deref(&self) -> &Self::Target {
        self.get()
    }
}

impl<F: TestFixture> std::ops::DerefMut for FixtureGuard<F> {
    fn deref_mut(&mut self) -> &mut Self::Target {
        self.get_mut()
    }
}

/// Context for integration tests that manages fixtures and test client.
///
/// Provides a structured way to run multi-step integration tests with
/// automatic fixture management and test isolation.
///
/// # Example
///
/// ```ignore
/// use fastapi_core::testing::{IntegrationTest, TestFixture};
/// use std::sync::Arc;
///
/// // Define a fixture (e.g., for database state)
/// struct TestData {
///     user_id: i64,
/// }
///
/// impl TestFixture for TestData {
///     fn setup() -> Self {
///         // Create test data
///         TestData { user_id: 1 }
///     }
///
///     fn teardown(&mut self) {
///         // Clean up test data
///     }
/// }
///
/// #[test]
/// fn test_user_api() {
///     let app = Arc::new(App::builder()
///         .route("/users/{id}", Method::Get, get_user)
///         .build());
///
///     IntegrationTest::new("User API Test", app)
///         .with_fixture::<TestData>()
///         .run(|ctx| {
///             // Access fixture
///             let data = ctx.fixture::<TestData>().unwrap();
///
///             // Make requests through the full app stack
///             let response = ctx.get(&format!("/users/{}", data.user_id)).send();
///             assert_eq!(response.status().as_u16(), 200);
///         });
/// }
/// ```
pub struct IntegrationTest<H: Handler + 'static> {
    /// Test name.
    name: String,
    /// Test client wrapping the app.
    client: TestClient<H>,
    /// Registered fixtures (type-erased).
    fixtures: HashMap<std::any::TypeId, Box<dyn std::any::Any + Send>>,
    /// State reset hooks to run between tests.
    reset_hooks: Vec<Box<dyn Fn() + Send + Sync>>,
}

impl<H: Handler + 'static> IntegrationTest<H> {
    /// Creates a new integration test context.
    pub fn new(name: impl Into<String>, handler: H) -> Self {
        Self {
            name: name.into(),
            client: TestClient::new(handler),
            fixtures: HashMap::new(),
            reset_hooks: Vec::new(),
        }
    }

    /// Creates a new integration test with a specific seed for determinism.
    pub fn with_seed(name: impl Into<String>, handler: H, seed: u64) -> Self {
        Self {
            name: name.into(),
            client: TestClient::with_seed(handler, seed),
            fixtures: HashMap::new(),
            reset_hooks: Vec::new(),
        }
    }

    /// Registers a fixture type for this test.
    ///
    /// The fixture will be set up before the test runs and torn down after.
    #[must_use]
    pub fn with_fixture<F: TestFixture + 'static>(mut self) -> Self {
        let guard = FixtureGuard::<F>::new();
        self.fixtures
            .insert(std::any::TypeId::of::<F>(), Box::new(guard));
        self
    }

    /// Registers a state reset hook to run after the test.
    ///
    /// Useful for clearing caches, resetting global state, etc.
    #[must_use]
    pub fn on_reset<F: Fn() + Send + Sync + 'static>(mut self, f: F) -> Self {
        self.reset_hooks.push(Box::new(f));
        self
    }

    /// Runs the integration test.
    ///
    /// The test function receives an `IntegrationTestContext` that provides
    /// access to the test client and fixtures.
    pub fn run<F>(mut self, test_fn: F)
    where
        F: FnOnce(&IntegrationTestContext<'_, H>) + std::panic::UnwindSafe,
    {
        // Create context
        let ctx = IntegrationTestContext {
            name: &self.name,
            client: &self.client,
            fixtures: &self.fixtures,
        };

        // Wrap context for panic safety
        let ctx_ref = std::panic::AssertUnwindSafe(&ctx);

        // Run test and capture result
        let result = std::panic::catch_unwind(|| {
            test_fn(&ctx_ref);
        });

        // Run reset hooks regardless of outcome
        for hook in &self.reset_hooks {
            hook();
        }

        // Clear cookies and dependency overrides
        self.client.clear_cookies();
        self.client.clear_dependency_overrides();

        // Drop fixtures in reverse order (triggers teardown)
        self.fixtures.clear();

        // Re-panic if test failed
        if let Err(e) = result {
            std::panic::resume_unwind(e);
        }
    }
}

/// Context available during an integration test.
pub struct IntegrationTestContext<'a, H: Handler> {
    /// Test name.
    name: &'a str,
    /// Test client.
    client: &'a TestClient<H>,
    /// Registered fixtures.
    fixtures: &'a HashMap<std::any::TypeId, Box<dyn std::any::Any + Send>>,
}

impl<'a, H: Handler + 'static> IntegrationTestContext<'a, H> {
    /// Returns the test name.
    #[must_use]
    pub fn name(&self) -> &str {
        self.name
    }

    /// Returns the test client.
    #[must_use]
    pub fn client(&self) -> &TestClient<H> {
        self.client
    }

    /// Gets a reference to a registered fixture.
    ///
    /// Returns `None` if the fixture type was not registered.
    #[must_use]
    pub fn fixture<F: TestFixture + 'static>(&self) -> Option<&F> {
        self.fixtures
            .get(&std::any::TypeId::of::<F>())
            .and_then(|boxed| boxed.downcast_ref::<FixtureGuard<F>>())
            .map(FixtureGuard::get)
    }

    /// Gets a mutable reference to a registered fixture.
    ///
    /// Returns `None` if the fixture type was not registered.
    #[must_use]
    pub fn fixture_mut<F: TestFixture + 'static>(&self) -> Option<&mut F> {
        // This is safe because we only expose mutable access to the fixture content,
        // not to the guard itself. The borrow checker ensures single-threaded access.
        // Note: This requires interior mutability in the fixture or careful usage.
        None // Conservative: don't allow mutable access through shared ref
    }

    // Delegate HTTP methods to client for convenience

    /// Starts building a GET request.
    pub fn get(&self, path: &str) -> RequestBuilder<'_, H> {
        self.client.get(path)
    }

    /// Starts building a POST request.
    pub fn post(&self, path: &str) -> RequestBuilder<'_, H> {
        self.client.post(path)
    }

    /// Starts building a PUT request.
    pub fn put(&self, path: &str) -> RequestBuilder<'_, H> {
        self.client.put(path)
    }

    /// Starts building a DELETE request.
    pub fn delete(&self, path: &str) -> RequestBuilder<'_, H> {
        self.client.delete(path)
    }

    /// Starts building a PATCH request.
    pub fn patch(&self, path: &str) -> RequestBuilder<'_, H> {
        self.client.patch(path)
    }

    /// Starts building an OPTIONS request.
    pub fn options(&self, path: &str) -> RequestBuilder<'_, H> {
        self.client.options(path)
    }

    /// Starts building a request with a custom method.
    pub fn request(&self, method: Method, path: &str) -> RequestBuilder<'_, H> {
        self.client.request(method, path)
    }
}

// =============================================================================
// TestServer Unit Tests
// =============================================================================

#[cfg(test)]
mod test_server_tests {
    use super::*;
    use crate::app::App;
    use std::net::TcpStream as StdTcpStreamAlias;

    fn make_test_app() -> App {
        App::builder()
            .get("/health", |_ctx: &RequestContext, _req: &mut Request| {
                std::future::ready(
                    Response::ok()
                        .header("content-type", b"text/plain".to_vec())
                        .body(ResponseBody::Bytes(b"OK".to_vec())),
                )
            })
            .get("/hello", |_ctx: &RequestContext, _req: &mut Request| {
                std::future::ready(
                    Response::ok()
                        .header("content-type", b"application/json".to_vec())
                        .body(ResponseBody::Bytes(
                            br#"{"message":"Hello, World!"}"#.to_vec(),
                        )),
                )
            })
            .post("/echo", |_ctx: &RequestContext, req: &mut Request| {
                let body = match req.body() {
                    Body::Bytes(b) => b.clone(),
                    _ => Vec::new(),
                };
                std::future::ready(
                    Response::ok()
                        .header("content-type", b"application/octet-stream".to_vec())
                        .body(ResponseBody::Bytes(body)),
                )
            })
            .build()
    }

    fn send_request(addr: SocketAddr, request: &[u8]) -> String {
        let mut stream = StdTcpStreamAlias::connect(addr).expect("Failed to connect to TestServer");
        stream
            .set_read_timeout(Some(Duration::from_secs(5)))
            .expect("set_read_timeout");
        stream.write_all(request).expect("Failed to write request");
        stream.flush().expect("Failed to flush");

        let mut buf = vec![0u8; 65536];
        let n = stream.read(&mut buf).expect("Failed to read response");
        String::from_utf8_lossy(&buf[..n]).to_string()
    }

    #[test]
    fn test_server_starts_and_responds() {
        let app = make_test_app();
        let server = TestServer::start(app);

        let response = send_request(
            server.addr(),
            b"GET /health HTTP/1.1\r\nHost: localhost\r\n\r\n",
        );

        assert!(
            response.contains("200 OK"),
            "Expected 200 OK, got: {response}"
        );
        assert!(response.contains("OK"), "Expected body 'OK'");
    }

    #[test]
    fn test_server_json_response() {
        let app = make_test_app();
        let server = TestServer::start(app);

        let response = send_request(
            server.addr(),
            b"GET /hello HTTP/1.1\r\nHost: localhost\r\n\r\n",
        );

        assert!(response.contains("200 OK"));
        assert!(response.contains("application/json"));
        assert!(response.contains(r#"{"message":"Hello, World!"}"#));
    }

    #[test]
    fn test_server_post_with_body() {
        let app = make_test_app();
        let server = TestServer::start(app);

        let request =
            b"POST /echo HTTP/1.1\r\nHost: localhost\r\nContent-Length: 11\r\n\r\nHello World";
        let response = send_request(server.addr(), request);

        assert!(response.contains("200 OK"));
        assert!(response.contains("Hello World"));
    }

    #[test]
    fn test_server_logs_requests() {
        let app = make_test_app();
        let server = TestServer::start(app);

        // Make a request
        send_request(
            server.addr(),
            b"GET /health HTTP/1.1\r\nHost: localhost\r\n\r\n",
        );

        let logs = server.log_entries();
        assert_eq!(logs.len(), 1);
        assert_eq!(logs[0].method, "GET");
        assert_eq!(logs[0].path, "/health");
        assert_eq!(logs[0].status, 200);
    }

    #[test]
    fn test_server_request_count() {
        let app = make_test_app();
        let server = TestServer::start(app);

        assert_eq!(server.request_count(), 0);

        send_request(
            server.addr(),
            b"GET /health HTTP/1.1\r\nHost: localhost\r\n\r\n",
        );
        send_request(
            server.addr(),
            b"GET /hello HTTP/1.1\r\nHost: localhost\r\n\r\n",
        );

        assert_eq!(server.request_count(), 2);
    }

    #[test]
    fn test_server_clear_logs() {
        let app = make_test_app();
        let server = TestServer::start(app);

        send_request(
            server.addr(),
            b"GET /health HTTP/1.1\r\nHost: localhost\r\n\r\n",
        );
        assert_eq!(server.request_count(), 1);

        server.clear_logs();
        assert_eq!(server.request_count(), 0);
    }

    #[test]
    fn test_server_url_helpers() {
        let app = make_test_app();
        let server = TestServer::start(app);

        assert!(server.url().starts_with("http://127.0.0.1:"));
        assert!(server.url_for("/health").ends_with("/health"));
        assert!(server.url_for("health").ends_with("/health"));
        assert!(server.port() > 0);
    }

    #[test]
    fn test_server_shutdown() {
        let app = make_test_app();
        let server = TestServer::start(app);
        let addr = server.addr();

        // Server should respond before shutdown
        let response = send_request(addr, b"GET /health HTTP/1.1\r\nHost: localhost\r\n\r\n");
        assert!(response.contains("200 OK"));

        // Signal shutdown
        server.shutdown();
        assert!(server.is_shutdown());
    }

    #[test]
    fn test_server_config_no_logging() {
        let app = make_test_app();
        let config = TestServerConfig::new().log_requests(false);
        let server = TestServer::start_with_config(app, config);

        send_request(
            server.addr(),
            b"GET /health HTTP/1.1\r\nHost: localhost\r\n\r\n",
        );

        // With logging disabled, no log entries should be recorded
        assert_eq!(server.request_count(), 0);
    }

    #[test]
    fn test_server_bad_request() {
        let app = make_test_app();
        let server = TestServer::start(app);

        // Send garbage data
        let response = send_request(server.addr(), b"NOT_HTTP_AT_ALL");

        assert!(response.contains("400 Bad Request"));
    }

    #[test]
    fn test_server_content_length_header() {
        let app = make_test_app();
        let server = TestServer::start(app);

        let response = send_request(
            server.addr(),
            b"GET /health HTTP/1.1\r\nHost: localhost\r\n\r\n",
        );

        // Response should include content-length
        assert!(
            response.contains("content-length: 2"),
            "Expected content-length: 2, got: {response}"
        );
    }

    #[test]
    fn test_server_multiple_requests_sequential() {
        let app = make_test_app();
        let server = TestServer::start(app);

        for _ in 0..5 {
            let response = send_request(
                server.addr(),
                b"GET /health HTTP/1.1\r\nHost: localhost\r\n\r\n",
            );
            assert!(response.contains("200 OK"));
        }

        assert_eq!(server.request_count(), 5);
    }

    #[test]
    fn test_server_log_entry_has_timing() {
        let app = make_test_app();
        let server = TestServer::start(app);

        send_request(
            server.addr(),
            b"GET /health HTTP/1.1\r\nHost: localhost\r\n\r\n",
        );

        let logs = server.log_entries();
        assert_eq!(logs.len(), 1);
        // Duration should be non-zero but reasonable (under 1 second)
        assert!(logs[0].duration < Duration::from_secs(1));
    }

    // =========================================================================
    // Graceful Shutdown E2E Tests (bd-14if)
    // =========================================================================

    #[test]
    fn test_server_shutdown_controller_available() {
        let app = make_test_app();
        let server = TestServer::start(app);

        // ShutdownController should be accessible
        let controller = server.shutdown_controller();
        assert!(!controller.is_shutting_down());
        assert_eq!(controller.phase(), crate::shutdown::ShutdownPhase::Running);
    }

    #[test]
    fn test_server_shutdown_triggers_controller() {
        let app = make_test_app();
        let server = TestServer::start(app);

        // Server should be running normally
        assert!(!server.shutdown_controller().is_shutting_down());

        // Trigger graceful shutdown
        server.shutdown();

        // Both the server flag and controller should reflect shutdown
        assert!(server.is_shutdown());
        assert!(server.shutdown_controller().is_shutting_down());
        assert_eq!(
            server.shutdown_controller().phase(),
            crate::shutdown::ShutdownPhase::StopAccepting
        );
    }

    #[test]
    fn test_server_requests_complete_before_shutdown() {
        let app = make_test_app();
        let server = TestServer::start(app);

        // Make a normal request before shutdown
        let response = send_request(
            server.addr(),
            b"GET /health HTTP/1.1\r\nHost: localhost\r\n\r\n",
        );
        assert!(response.contains("200 OK"));
        assert_eq!(server.request_count(), 1);

        // Signal shutdown
        server.shutdown();

        // Verify the request completed and was logged
        let logs = server.log_entries();
        assert_eq!(logs.len(), 1);
        assert_eq!(logs[0].status, 200);
        assert_eq!(logs[0].path, "/health");
    }

    #[test]
    fn test_server_in_flight_tracking() {
        let app = make_test_app();
        let server = TestServer::start(app);

        // Initially no in-flight requests
        assert_eq!(server.in_flight_count(), 0);

        // The in-flight guard is managed internally by the server loop,
        // so after request completion it should return to 0
        send_request(
            server.addr(),
            b"GET /health HTTP/1.1\r\nHost: localhost\r\n\r\n",
        );

        // Wait for the in-flight count to return to 0 (bd-2emz fix)
        // There's a small race between client receiving response and
        // server dropping the InFlightGuard, so we spin briefly.
        let start = std::time::Instant::now();
        let timeout = std::time::Duration::from_millis(500);
        while server.in_flight_count() > 0 && start.elapsed() < timeout {
            std::thread::sleep(std::time::Duration::from_millis(1));
        }
        assert_eq!(
            server.in_flight_count(),
            0,
            "In-flight count should return to 0 after request completes"
        );
    }

    #[test]
    fn test_server_in_flight_guard_tracks_correctly() {
        let app = make_test_app();
        let server = TestServer::start(app);

        // Manually track requests via the controller
        let controller = server.shutdown_controller();
        assert_eq!(controller.in_flight_count(), 0);

        let guard1 = controller.track_request();
        assert_eq!(controller.in_flight_count(), 1);

        let guard2 = controller.track_request();
        assert_eq!(controller.in_flight_count(), 2);

        drop(guard1);
        assert_eq!(controller.in_flight_count(), 1);

        drop(guard2);
        assert_eq!(controller.in_flight_count(), 0);
    }

    #[test]
    fn test_server_shutdown_hooks_executed() {
        let app = make_test_app();
        let server = TestServer::start(app);

        // Register shutdown hooks
        let hook_executed = Arc::new(AtomicBool::new(false));
        let hook_executed_clone = Arc::clone(&hook_executed);
        server.shutdown_controller().register_hook(move || {
            hook_executed_clone.store(true, std::sync::atomic::Ordering::Release);
        });

        assert!(!hook_executed.load(std::sync::atomic::Ordering::Acquire));

        // Trigger shutdown — hooks run in the server loop when it exits
        server.shutdown();

        // Wait for background thread to finish
        // Drop the server to join the thread
        drop(server);

        assert!(
            hook_executed.load(std::sync::atomic::Ordering::Acquire),
            "Shutdown hook should have been executed"
        );
    }

    #[test]
    fn test_server_multiple_shutdown_hooks_lifo() {
        let app = make_test_app();
        let server = TestServer::start(app);

        let execution_order = Arc::new(Mutex::new(Vec::new()));

        let order1 = Arc::clone(&execution_order);
        server.shutdown_controller().register_hook(move || {
            order1.lock().push(1);
        });

        let order2 = Arc::clone(&execution_order);
        server.shutdown_controller().register_hook(move || {
            order2.lock().push(2);
        });

        let order3 = Arc::clone(&execution_order);
        server.shutdown_controller().register_hook(move || {
            order3.lock().push(3);
        });

        // Trigger shutdown and wait for thread to finish
        server.shutdown();
        drop(server);

        // Hooks should run in LIFO order (3, 2, 1)
        let order = execution_order.lock();
        assert_eq!(*order, vec![3, 2, 1]);
    }

    #[test]
    fn test_server_shutdown_controller_phase_progression() {
        let app = make_test_app();
        let server = TestServer::start(app);

        let controller = server.shutdown_controller();
        assert_eq!(controller.phase(), crate::shutdown::ShutdownPhase::Running);

        // Advance through phases manually
        assert!(controller.advance_phase());
        assert_eq!(
            controller.phase(),
            crate::shutdown::ShutdownPhase::StopAccepting
        );

        assert!(controller.advance_phase());
        assert_eq!(
            controller.phase(),
            crate::shutdown::ShutdownPhase::ShutdownFlagged
        );

        assert!(controller.advance_phase());
        assert_eq!(
            controller.phase(),
            crate::shutdown::ShutdownPhase::GracePeriod
        );

        assert!(controller.advance_phase());
        assert_eq!(
            controller.phase(),
            crate::shutdown::ShutdownPhase::Cancelling
        );

        assert!(controller.advance_phase());
        assert_eq!(
            controller.phase(),
            crate::shutdown::ShutdownPhase::RunningHooks
        );

        assert!(controller.advance_phase());
        assert_eq!(controller.phase(), crate::shutdown::ShutdownPhase::Stopped);

        // Can't go past Stopped
        assert!(!controller.advance_phase());
    }

    #[test]
    fn test_server_receiver_notified_on_shutdown() {
        let app = make_test_app();
        let server = TestServer::start(app);

        let receiver = server.shutdown_controller().subscribe();
        assert!(!receiver.is_shutting_down());

        server.shutdown();
        assert!(receiver.is_shutting_down());
        assert!(!receiver.is_forced());
    }

    #[test]
    fn test_server_forced_shutdown() {
        let app = make_test_app();
        let server = TestServer::start(app);

        let receiver = server.shutdown_controller().subscribe();

        // First shutdown -> graceful
        server.shutdown_controller().shutdown();
        assert!(receiver.is_shutting_down());
        assert!(!receiver.is_forced());

        // Second shutdown -> forced
        server.shutdown_controller().shutdown();
        assert!(receiver.is_forced());
    }

    #[test]
    fn test_server_requests_work_before_shutdown_signal() {
        let app = make_test_app();
        let server = TestServer::start(app);

        // Multiple requests work fine before any shutdown signal
        for i in 0..3 {
            let response = send_request(
                server.addr(),
                b"GET /health HTTP/1.1\r\nHost: localhost\r\n\r\n",
            );
            assert!(
                response.contains("200 OK"),
                "Request {i} should succeed before shutdown"
            );
        }

        assert_eq!(server.request_count(), 3);

        // Now shutdown
        server.shutdown();
        assert!(server.is_shutdown());
    }
}