jerrycan_core/

test_client.rs

//! In-memory test client (spec §4.1 "Test client"): no sockets, no network.
//! `override_dep` is THE testing seam — fake any dependency, run real requests.
//!
//! Panics in handlers propagate in tests by design — the serve path converts them to 500 JC0500.

use crate::App;
use crate::app::{BuiltApp, Policy};
use crate::clock::Clock;
use crate::error::Error;
use crate::response::{IntoResponse, Response};
use bytes::Bytes;
use http::{Method, StatusCode, header};
use http_body_util::BodyExt;
use serde::Serialize;
use serde::de::DeserializeOwned;
use std::any::TypeId;
use std::sync::Arc;

/// One part for [`TestApp::post_multipart`].
pub struct TestPart {
    name: String,
    filename: Option<String>,
    content_type: Option<String>,
    data: Bytes,
}

impl TestPart {
    /// A simple form field.
    pub fn text(name: &str, value: &str) -> Self {
        Self {
            name: name.to_string(),
            filename: None,
            content_type: None,
            data: Bytes::copy_from_slice(value.as_bytes()),
        }
    }
    /// A file-upload field.
    pub fn file(name: &str, filename: &str, content_type: &str, data: &[u8]) -> Self {
        Self {
            name: name.to_string(),
            filename: Some(filename.to_string()),
            content_type: Some(content_type.to_string()),
            data: Bytes::copy_from_slice(data),
        }
    }
}

/// Deterministic boundary (determinism is a framework invariant — no
/// randomness in generated bytes). Part data containing the wire delimiter
/// would silently corrupt the assembled request, so the helper debug-asserts
/// against it instead of trusting improbability.
const TEST_BOUNDARY: &str = "jerrycan-test-boundary-7f3a";

impl App {
    /// Build for testing. Panics on build errors — a test should fail loudly.
    ///
    /// Swaps the default real [`Clock`] for a controllable [`Clock::test`] via
    /// the override seam (overrides outrank the app's `Clock::system` singleton)
    /// and keeps a handle on the same clock — [`TestApp::clock`] returns it, so
    /// `advance`/`set` move the very clock handlers resolve.
    pub fn into_test(self) -> TestApp {
        let mut built = self.build().expect("app failed to build");
        let clock = Clock::test();
        let mut overrides = (*built.overrides).clone();
        overrides.insert(
            TypeId::of::<Clock>(),
            Arc::new(clock.clone()) as crate::dep::AnyArc,
        );
        built.overrides = Arc::new(overrides);
        TestApp { built, clock }
    }
}

pub struct TestApp {
    built: BuiltApp,
    /// The test clock handed to handlers via the override above. Shares its
    /// offset with the resolved copy (`Clock` clones share one `Arc`), so
    /// `clock().advance(..)` is observable through real requests.
    clock: Clock,
}

impl TestApp {
    /// Replace the provider for `T` everywhere (values AND factories) for all
    /// subsequent requests. Chainable.
    pub fn override_dep<T: Send + Sync + 'static>(mut self, value: T) -> Self {
        let mut map = (*self.built.overrides).clone();
        map.insert(TypeId::of::<T>(), Arc::new(value) as crate::dep::AnyArc);
        self.built.overrides = Arc::new(map);
        self
    }

    /// The controllable [`Clock`] injected for this test. `advance`/`set` it to
    /// move domain time (rate windows, schedules, expiry) under the app; the
    /// change is visible to every subsequent request and task context.
    pub fn clock(&self) -> Clock {
        self.clock.clone()
    }

    /// A [`TaskContext`](crate::TaskContext) for resolving app-level dependencies
    /// outside a request, honoring any `override_dep` fakes set on this `TestApp`.
    ///
    /// Only **app-level** dependencies (those registered with `App::provide` /
    /// `App::provide_dep`) are resolvable; module-scoped providers are not in
    /// scope here.
    pub fn task_context(&self) -> crate::TaskContext {
        self.built.task_context()
    }

    pub async fn get(&self, path: &str) -> TestResponse {
        self.request_json(Method::GET, path, None).await
    }
    pub async fn delete(&self, path: &str) -> TestResponse {
        self.request_json(Method::DELETE, path, None).await
    }
    pub async fn post_json<B: Serialize>(&self, path: &str, body: &B) -> TestResponse {
        self.request_json(
            Method::POST,
            path,
            Some(serde_json::to_vec(body).expect("serialize")),
        )
        .await
    }
    pub async fn put_json<B: Serialize>(&self, path: &str, body: &B) -> TestResponse {
        self.request_json(
            Method::PUT,
            path,
            Some(serde_json::to_vec(body).expect("serialize")),
        )
        .await
    }
    pub async fn patch_json<B: Serialize>(&self, path: &str, body: &B) -> TestResponse {
        self.request_json(
            Method::PATCH,
            path,
            Some(serde_json::to_vec(body).expect("serialize")),
        )
        .await
    }

    /// A CORS preflight (`OPTIONS`) request with headers.
    pub async fn options_with(&self, path: &str, headers: &[(&str, &str)]) -> TestResponse {
        self.request(http::Method::OPTIONS, path, headers, None)
            .await
    }

    /// A by-method request with headers and an optional body. The generic seam the
    /// `*_with` helpers don't cover (OPTIONS, HEAD, custom flows). No simulated
    /// peer address — use `request_from` for the IP-partition rate-limit tier.
    pub async fn request(
        &self,
        method: http::Method,
        path: &str,
        headers: &[(&str, &str)],
        body: Option<&[u8]>,
    ) -> TestResponse {
        self.send(
            method,
            path,
            body.map(Bytes::copy_from_slice),
            None,
            headers,
            None,
        )
        .await
    }

    /// POST a raw byte body (content-type `application/octet-stream`). Routes
    /// and per-route body limits apply exactly as they do over a socket.
    pub async fn post_bytes(&self, path: &str, bytes: &[u8]) -> TestResponse {
        self.post_bytes_with(path, bytes, &[]).await
    }

    /// POST a raw byte body with explicit request headers.
    pub async fn post_bytes_with(
        &self,
        path: &str,
        bytes: &[u8],
        headers: &[(&str, &str)],
    ) -> TestResponse {
        self.send(
            Method::POST,
            path,
            Some(Bytes::copy_from_slice(bytes)),
            Some("application/octet-stream"),
            headers,
            None,
        )
        .await
    }

    /// POSTs a `multipart/form-data` request assembled from `parts`.
    pub async fn post_multipart(&self, path: &str, parts: &[TestPart]) -> TestResponse {
        self.post_multipart_with(path, parts, &[]).await
    }

    /// `post_multipart` with extra request headers (e.g. auth cookies).
    pub async fn post_multipart_with(
        &self,
        path: &str,
        parts: &[TestPart],
        headers: &[(&str, &str)],
    ) -> TestResponse {
        let mut body = Vec::new();
        for part in parts {
            debug_assert!(
                !part
                    .data
                    .windows(TEST_BOUNDARY.len() + 4)
                    .any(|w| w[..4] == *b"\r\n--" && &w[4..] == TEST_BOUNDARY.as_bytes()),
                "TestPart data contains the multipart delimiter — the assembled request would corrupt"
            );
            body.extend_from_slice(format!("--{TEST_BOUNDARY}\r\n").as_bytes());
            match &part.filename {
                Some(filename) => body.extend_from_slice(
                    format!(
                        "content-disposition: form-data; name=\"{}\"; filename=\"{}\"\r\n",
                        part.name, filename
                    )
                    .as_bytes(),
                ),
                None => body.extend_from_slice(
                    format!("content-disposition: form-data; name=\"{}\"\r\n", part.name)
                        .as_bytes(),
                ),
            }
            if let Some(content_type) = &part.content_type {
                body.extend_from_slice(format!("content-type: {content_type}\r\n").as_bytes());
            }
            body.extend_from_slice(b"\r\n");
            body.extend_from_slice(&part.data);
            body.extend_from_slice(b"\r\n");
        }
        body.extend_from_slice(format!("--{TEST_BOUNDARY}--\r\n").as_bytes());
        let content_type = format!("multipart/form-data; boundary={TEST_BOUNDARY}");
        self.send(
            Method::POST,
            path,
            Some(Bytes::from(body)),
            Some(&content_type),
            headers,
            None,
        )
        .await
    }

    /// GET with explicit request headers (auth tests, content negotiation).
    pub async fn get_with(&self, path: &str, headers: &[(&str, &str)]) -> TestResponse {
        self.request_with(Method::GET, path, None, headers).await
    }

    /// Like `get`, but also sets the simulated client socket address (for the
    /// rate-limiter's IP partition tier).
    pub async fn get_from(&self, path: &str, peer: std::net::SocketAddr) -> TestResponse {
        self.send(Method::GET, path, None, None, &[], Some(peer))
            .await
    }

    /// A by-method request with headers AND a simulated peer address.
    pub async fn request_from(
        &self,
        method: http::Method,
        path: &str,
        headers: &[(&str, &str)],
        peer: std::net::SocketAddr,
    ) -> TestResponse {
        self.send(method, path, None, None, headers, Some(peer))
            .await
    }

    /// POST JSON with explicit request headers.
    pub async fn post_json_with<B: Serialize>(
        &self,
        path: &str,
        body: &B,
        headers: &[(&str, &str)],
    ) -> TestResponse {
        self.request_with(
            Method::POST,
            path,
            Some(serde_json::to_vec(body).expect("serialize")),
            headers,
        )
        .await
    }

    /// DELETE with explicit request headers (guarded-route auth tests).
    pub async fn delete_with(&self, path: &str, headers: &[(&str, &str)]) -> TestResponse {
        self.request_with(Method::DELETE, path, None, headers).await
    }

    /// PUT JSON with explicit request headers.
    pub async fn put_json_with<B: Serialize>(
        &self,
        path: &str,
        body: &B,
        headers: &[(&str, &str)],
    ) -> TestResponse {
        self.request_with(
            Method::PUT,
            path,
            Some(serde_json::to_vec(body).expect("serialize")),
            headers,
        )
        .await
    }

    /// PATCH JSON with explicit request headers.
    pub async fn patch_json_with<B: Serialize>(
        &self,
        path: &str,
        body: &B,
        headers: &[(&str, &str)],
    ) -> TestResponse {
        self.request_with(
            Method::PATCH,
            path,
            Some(serde_json::to_vec(body).expect("serialize")),
            headers,
        )
        .await
    }

    async fn request_json(
        &self,
        method: Method,
        path: &str,
        json: Option<Vec<u8>>,
    ) -> TestResponse {
        self.request_with(method, path, json, &[]).await
    }

    async fn request_with(
        &self,
        method: Method,
        path: &str,
        json: Option<Vec<u8>>,
        headers: &[(&str, &str)],
    ) -> TestResponse {
        let content_type = json.as_ref().map(|_| "application/json");
        self.send(
            method,
            path,
            json.map(Bytes::from),
            content_type,
            headers,
            None,
        )
        .await
    }

    /// The single test request path: build the head, run the SAME two-phase
    /// policy the live server runs (route before body, per-route limit), then
    /// dispatch. Stream routes get a real framed lane with the route's `Limited`
    /// cap inside it (the equivalent of `Limited` over a socket); buffered routes
    /// keep the upfront length check on the already-buffered bytes. Either way
    /// this keeps 404-before-read and per-route 413 honest in tests.
    async fn send(
        &self,
        method: Method,
        path: &str,
        body: Option<Bytes>,
        content_type: Option<&str>,
        headers: &[(&str, &str)],
        peer: Option<std::net::SocketAddr>,
    ) -> TestResponse {
        let mut builder = http::Request::builder().method(method).uri(path);
        // Apply the helper's default content-type only when the explicit headers
        // don't already set one — otherwise an explicit `content-type` (e.g. a
        // `multipart/form-data` boundary) would be shadowed by the default, since
        // `HeaderMap::get` returns the first value inserted.
        let explicit_ct = headers
            .iter()
            .any(|(name, _)| name.eq_ignore_ascii_case("content-type"));
        if let Some(ct) = content_type
            && !explicit_ct
        {
            builder = builder.header(header::CONTENT_TYPE, ct);
        }
        for (name, value) in headers {
            builder = builder.header(*name, *value);
        }
        let req = builder.body(()).expect("test request build");
        let (mut parts, ()) = req.into_parts();
        // Inject the simulated peer the same way the serve loop does, so IP-based
        // rate-limit tests run in-memory with the address already on the request.
        if let Some(peer) = peer {
            parts.extensions.insert(crate::extract::ClientAddr(peer));
        }
        let body = body.unwrap_or_default();
        // Capture the request Origin before `parts` is moved into dispatch, so the
        // in-process 413 path mirrors serve.rs's `finish_error` and CORS-decorates
        // a cross-origin over-limit response.
        let cors_origin = parts.headers.get(http::header::ORIGIN).cloned();

        // Phase 1: route on the head alone — a reject answers without reading the body.
        let (limit, stream) = match self.built.route_policy(&parts) {
            Policy::Reject(response) => return TestResponse::collect(response).await,
            Policy::Route { limit, stream } => (limit, stream),
        };
        // Phase 2: stream routes get a REAL stream lane — frames + the route's
        // `Limited` cap inside it, exactly like the live socket path, so the
        // cumulative cap (and frame straddling) are honest in tests too. The
        // buffered path keeps its upfront length check.
        let lane = if stream {
            crate::extract::BodyLane::Stream(Some(test_stream_lane(body, limit)))
        } else {
            if body.len() > limit {
                let mut response = Error::payload_too_large().into_response();
                if self.built.security_headers {
                    crate::app::apply_security_headers(&mut response);
                }
                if let Some(config) = &self.built.cors {
                    crate::cors::apply_cors(&mut response, cors_origin.as_ref(), config);
                }
                return TestResponse::collect(response).await;
            }
            crate::extract::BodyLane::Buffered(body)
        };
        TestResponse::collect(self.built.dispatch(parts, lane).await).await
    }
}

/// A test-only stream lane: chop the buffered body into 13-byte frames so every
/// test on a stream route exercises frame straddling for free, then wrap in the
/// route's `Limited` cap so the cumulative cap trips in-process exactly as it
/// does over a socket.
fn test_stream_lane(body: Bytes, limit: usize) -> crate::extract::StreamLane {
    struct Frames(std::collections::VecDeque<Bytes>);
    impl http_body::Body for Frames {
        type Data = Bytes;
        type Error = Box<dyn std::error::Error + Send + Sync>;
        fn poll_frame(
            mut self: std::pin::Pin<&mut Self>,
            _cx: &mut std::task::Context<'_>,
        ) -> std::task::Poll<Option<Result<http_body::Frame<Bytes>, Self::Error>>> {
            std::task::Poll::Ready(self.0.pop_front().map(|b| Ok(http_body::Frame::data(b))))
        }
    }
    let frames = body.chunks(13).map(Bytes::copy_from_slice).collect();
    // `Limited<Frames>::Error` is already `Box<dyn Error + Send + Sync>` (Frames'
    // error type), so the cap maps straight into the lane's error channel.
    let limited = http_body_util::Limited::new(Frames(frames), limit);
    http_body_util::combinators::UnsyncBoxBody::new(limited)
}

pub struct TestResponse {
    status: StatusCode,
    headers: http::HeaderMap,
    body: Bytes,
}

impl TestResponse {
    async fn collect(res: Response) -> Self {
        let (parts, body) = res.into_parts();
        let body = body
            .collect()
            // A buffered body cannot fail; a streaming one can fail mid-stream.
            .await
            .unwrap_or_else(|e| panic!("response body failed mid-stream: {e}"))
            .to_bytes();
        Self {
            status: parts.status,
            headers: parts.headers,
            body,
        }
    }

    pub fn status(&self) -> StatusCode {
        self.status
    }
    pub fn headers(&self) -> &http::HeaderMap {
        &self.headers
    }
    pub fn text(&self) -> String {
        String::from_utf8_lossy(&self.body).into_owned()
    }

    /// The raw response body — for binary downloads where `text()` would mangle.
    pub fn bytes(&self) -> &[u8] {
        &self.body
    }

    /// Deserialize the JSON body, with a readable panic on mismatch.
    pub fn json<T: DeserializeOwned>(&self) -> T {
        serde_json::from_slice(&self.body).unwrap_or_else(|e| {
            panic!(
                "response body is not the expected JSON shape: {e}\nbody: {}",
                self.text()
            )
        })
    }
}

#[cfg(test)]
mod tests {
    use crate::prelude::*;

    #[tokio::test]
    async fn post_multipart_builds_a_parseable_request() {
        use crate::multipart::Multipart;
        async fn upload(mut mp: Multipart) -> Result<Json<Vec<String>>> {
            let mut seen = Vec::new();
            while let Some(part) = mp.next_part().await? {
                let label = match part.filename() {
                    Some(f) => format!("{}:{}", part.name(), f),
                    None => part.name().to_string(),
                };
                let len = part.bytes().await?.len();
                seen.push(format!("{label}({len})"));
            }
            Ok(Json(seen))
        }
        let t = App::new()
            .route("/upload", post(upload).stream_body())
            .into_test();
        let res = t
            .post_multipart(
                "/upload",
                &[
                    TestPart::text("title", "Q3 leads"),
                    TestPart::file("csv", "leads.csv", "text/csv", b"a,b\n1,2\n"),
                ],
            )
            .await;
        assert_eq!(res.status().as_u16(), 200, "body: {}", res.text());
        assert_eq!(
            res.json::<Vec<String>>(),
            vec!["title(8)".to_string(), "csv:leads.csv(8)".to_string()]
        );
    }

    #[tokio::test]
    async fn test_response_exposes_raw_bytes() {
        async fn download() -> StreamBody {
            let (body, tx) = StreamBody::channel();
            tokio::spawn(async move {
                let _ = tx.send(&b"\x00\x01binary"[..]).await;
            });
            body.content_type("application/octet-stream")
        }
        let t = App::new().route("/dl", get(download)).into_test();
        let res = t.get("/dl").await;
        assert_eq!(res.bytes(), b"\x00\x01binary");
    }

    /// `post_multipart_with` must carry extra request headers alongside the
    /// generated multipart body: the handler sees `x-auth` AND parses the parts.
    #[tokio::test]
    async fn post_multipart_with_carries_extra_headers() {
        use crate::multipart::Multipart;
        async fn upload(headers: Headers, mut mp: Multipart) -> Result<Json<(bool, usize)>> {
            let authed = headers.get("x-auth").is_some();
            let mut parts = 0;
            while let Some(part) = mp.next_part().await? {
                let _ = part.bytes().await?;
                parts += 1;
            }
            Ok(Json((authed, parts)))
        }
        let t = App::new()
            .route("/upload", post(upload).stream_body())
            .into_test();
        let res = t
            .post_multipart_with(
                "/upload",
                &[TestPart::text("field", "value")],
                &[("x-auth", "token")],
            )
            .await;
        assert_eq!(res.status().as_u16(), 200, "body: {}", res.text());
        assert_eq!(res.json::<(bool, usize)>(), (true, 1));
    }

    /// `into_test` injects the SAME clock `TestApp::clock()` returns: advancing
    /// the handle must be visible to a dep resolved through a task context —
    /// the path background jobs use to read domain time.
    #[tokio::test]
    async fn test_clock_handle_drives_resolved_clock_in_task_context() {
        let t = App::new().into_test();
        let mut ctx = t.task_context();
        let resolved = ctx.resolve::<Clock>().await.unwrap();
        let before = resolved.now();
        t.clock().advance(std::time::Duration::from_secs(60));
        assert_eq!(
            resolved.now().duration_since(before).unwrap(),
            std::time::Duration::from_secs(60),
            "TestApp::clock() and the resolved Clock share one offset",
        );
    }
}