Struct PtyBackend 

pub struct PtyBackend { /* private fields */ }

Available on crate feature pty-test only.

Drives the real crate::run flush pipeline into an in-process byte sink, so escape-code / color-depth / image-protocol output is asserted end-to-end — the byte/protocol tier that TestBackend’s buffer-only model deliberately cannot reach (see tests/visual_snapshots.rs).

Each render constructs a fresh fullscreen Terminal whose sink is a captured Vec<u8> (no real TTY, no raw mode), runs one frame through the same crate::frame_owned entry point the production loop uses, and captures the emitted bytes. Because the previous frame buffer starts empty, every frame emits a complete first-paint diff — fully deterministic and reproducible on a headless CI runner.

This type is gated behind the dev-only pty-test feature and is not present in a default build.

Since 0.21.0.

Example

use slt::{Color, PtyBackend};

let mut pb = PtyBackend::new(10, 1);
pb.render(|ui| {
    ui.text("x").fg(Color::Red).bold();
});
// The real flush pipeline emitted an SGR sequence for the styled glyph.
pb.assert_emits("\u{1b}[");

Implementations

impl PtyBackend

pub fn new(width: u32, height: u32) -> Self

Create a PTY capture backend with the given terminal dimensions.

Defaults to ColorDepth::TrueColor; override with with_color_depth.

pub fn with_color_depth(self, depth: ColorDepth) -> Self

Set the ColorDepth the flush pipeline encodes SGR colors with (e.g. truecolor vs 256-color). Returns self for chaining.

pub fn render(&mut self, f: impl FnOnce(&mut Context)) -> &PtyFrame

Render one frame through the real Terminal flush pipeline, capturing the emitted bytes. Returns the just-captured PtyFrame.

pub fn render_with_events( &mut self, events: Vec<Event>, f: impl FnOnce(&mut Context), ) -> &PtyFrame

Render one frame with injected input events, capturing the emitted bytes. Returns the just-captured PtyFrame.

pub fn frames_raw(&self) -> impl Iterator<Item = &[u8]>

Iterate the raw byte stream of every captured frame, oldest first.

pub fn last_raw(&self) -> &[u8]

Raw bytes of the most recently rendered frame.

Panics if no frame has been rendered yet.

pub fn assert_emits(&self, needle: &str)

Assert the last frame’s byte stream contains needle.

Panics with an escaped + hex dump of the emitted bytes on a miss.

pub fn assert_not_emits(&self, needle: &str)

Assert the last frame’s byte stream does not contain needle.

Panics with an escaped + hex dump on an unexpected hit.