In-process test harness for apps built on the standout CLI framework.

TestHarness bundles the scattered injection seams — environment detectors, env vars, working directory, stdin, clipboard, output mode, and tempdir fixtures — into a single fluent builder, and restores every override when the harness is dropped.

Example

use standout_test::TestHarness;
# fn example(app: &standout::cli::App, cmd: clap::Command) {
let result = TestHarness::new()
    .env("HOME", "/tmp/fake")
    .clipboard("pasted content")
    .terminal_width(80)
    .piped_stdin("extra input\n")
    .no_color()
    .fixture("notes/todo.txt", "- buy milk\n")
    .run(app, cmd, ["myapp", "notes", "list"]);

result.assert_success();
result.assert_stdout_contains("buy milk");
# }

Concurrency and restoration

The harness mutates process-global state (env vars, cwd, environment detectors, default input readers). Tests that instantiate a TestHarness must be annotated #[serial] (from the re-exported serial_test crate).

A Drop impl restores every override on both normal exit and panic unwind, with two nuances:

• Env vars and cwd are restored to the values captured at run() time.
• Terminal detectors and default input readers are reset to the library defaults, not to whatever was installed before run(). This matches the behavior of [standout_render::DetectorGuard]. Don't mix a TestHarness with a manually installed detector override on the same thread.