Struct TestApp 

pub struct TestApp { /* private fields */ }

Headless test harness. Creates an App with TestBackend for automated testing.

TestApp does NOT run the full async event loop. Instead, events are processed synchronously via process_event, allowing tests to control timing precisely.

Example

use textual_rs::testing::TestApp;
let test_app = TestApp::new(80, 24, || Box::new(MyScreen));

Implementations

impl TestApp

pub fn new( cols: u16, rows: u16, factory: impl FnOnce() -> Box<dyn Widget> + 'static, ) -> Self

Create a new TestApp with the given root screen factory.

Initializes the reactive runtime (safe to call multiple times), mounts the root screen, and renders the initial frame.

pub fn new_styled( cols: u16, rows: u16, css: &str, factory: impl FnOnce() -> Box<dyn Widget> + 'static, ) -> Self

Create a TestApp WITH built-in CSS (for tests that need proper widget layout).

pub fn pilot(&mut self) -> Pilot<'_>

Get a Pilot for sending simulated input events.

pub fn ctx(&self) -> &AppContext

Access the AppContext for state assertions (focus, widget ids, etc.).

pub fn buffer(&self) -> &Buffer

Access the rendered buffer for row-level assertions.

pub fn backend(&self) -> &TestBackend

Access the TestBackend directly (implements Display for insta snapshots).

pub fn inject_key_event(&mut self, key: KeyEvent)

Inject a key event without draining the message queue.

Used in tests that need to inspect the raw message queue immediately after key dispatch (e.g., to verify a specific message was posted before bubbling).

pub fn drain_messages(&self)

Drain the message queue explicitly (e.g., after inject_key_event).

pub fn process_event(&mut self, event: AppEvent)

Process a single event synchronously and re-render.

Used by Pilot to inject input. Can also be called directly for precise control.