Struct TestHarness 

pub struct TestHarness { /* private fields */ }

Fluent builder for in-process CLI tests.

See the crate-level docs for the usage pattern. The harness installs every override in TestHarness::run and tears them down on Drop, so a failed assertion never leaks state into the next test.

Implementations

impl TestHarness

pub fn new() -> Self

Creates an empty harness with no overrides applied.

pub fn env(self, key: impl Into<String>, value: impl Into<String>) -> Self

Sets key=value as a real environment variable for the duration of the run. Handlers that use EnvSource::new / std::env::var will see it.

pub fn env_remove(self, key: impl Into<String>) -> Self

Removes key from the real environment for the duration of the run.

pub fn terminal_width(self, cols: usize) -> Self

Forces the reported terminal width to cols.

pub fn no_terminal_width(self) -> Self

Forces terminal-width detection to report “unknown” (as if stdout is not a TTY).

pub fn is_tty(self) -> Self

Claims stdout is attached to a TTY.

pub fn no_tty(self) -> Self

Claims stdout is not a TTY (piped, redirected, …).

pub fn with_color(self) -> Self

Declares that the output target supports ANSI color.

pub fn no_color(self) -> Self

Declares that the output target does not support ANSI color. When --output=auto is used, this forces the Text render path.

pub fn output_mode(self, mode: OutputMode) -> Self

Forces a specific OutputMode regardless of the --output flag.

Internally this injects --<flag>=<mode> as the last argument when TestHarness::run is called. <flag> defaults to output; override it with output_flag_name for apps that renamed the flag via AppBuilder::output_flag(...).

pub fn output_flag_name(self, name: impl Into<String>) -> Self

Configures the CLI flag name used to force output_mode.

Defaults to "output" (matching AppBuilder’s default). Change it if the app under test was built with a renamed flag (e.g. AppBuilder::output_flag(Some("format"))).

No-op when output_mode isn’t set.

pub fn text_output(self) -> Self

Shortcut for output_mode(OutputMode::Text).

pub fn piped_stdin(self, content: impl Into<String>) -> Self

Simulates piped stdin with content. Handlers using StdinSource::new() will see is_terminal() == false and read content.

pub fn interactive_stdin(self) -> Self

Simulates an interactive terminal for stdin (no piped content).

pub fn clipboard(self, content: impl Into<String>) -> Self

Installs content as the mock clipboard. Handlers using ClipboardSource::new() will read it.

pub fn prompts(self, responder: Arc<dyn PromptResponder>) -> Self

Installs a PromptResponder that every .prompt() call on a standout_input interactive source will route through during the run.

Use this to test wizard / setup / REPL flows that call InquireText::new(...).prompt(), InquireSelect::new(...).prompt(), etc., without launching real prompts. The ScriptedResponder bundled with standout-input covers the common case:

use standout_input::{PromptResponse, ScriptedResponder};
use std::sync::Arc;

let result = TestHarness::new()
    .prompts(Arc::new(ScriptedResponder::new([
        PromptResponse::text("buy milk"),       // first text prompt
        PromptResponse::Bool(true),             // first confirm
        PromptResponse::Choice(2),              // first select -> options[2]
    ])))
    .run(&app, cmd, ["mycli", "setup"]);

The responder is installed via set_default_prompt_responder for the duration of the run and reset on drop, matching the stdin / clipboard pattern.

pub fn cwd(self, path: impl Into<PathBuf>) -> Self

Sets the working directory for the run to path.

If not set and any fixture is declared, the harness uses the fixture tempdir as the cwd.

pub fn fixture(self, path: impl AsRef<Path>, content: impl Into<String>) -> Self

Declares a file that should exist at path (relative to the fixture tempdir) with the given text content.

The first call to fixture creates a fresh tempfile::TempDir which becomes the default cwd. Access it via tempdir.

Panics

Panics if path is absolute or contains a .. component — both would let the fixture escape the harness-owned tempdir and potentially clobber files in the user’s real filesystem.

pub fn fixture_bytes( self, path: impl AsRef<Path>, content: impl Into<Vec<u8>>, ) -> Self

Declares a binary fixture file. Same as fixture but takes raw bytes. Applies the same path validation.

pub fn tempdir(&self) -> Option<&Path>

Returns the fixture tempdir path if one has been allocated.

Useful for constructing absolute paths to pass as handler arguments.

pub fn run<I, T>(self, app: &App, cmd: Command, args: I) -> TestResult

where I: IntoIterator<Item = T>, T: Into<OsString> + Clone,

Installs every override, runs app with the given cmd definition and argv, and returns a TestResult.

Overrides are torn down when the returned guard held inside the TestResult is dropped. The TestResult and the harness share the same lifetime, so a typical test binds the result and lets it fall out of scope at the end.

Trait Implementations

impl Default for TestHarness

fn default() -> Self

Returns the “default value” for a type.