Struct Harness 

pub struct Harness<A: App> { /* private fields */ }

Runs an App against an in-memory screen.

Every input method renders afterwards, like the real runtime does. Work of Command::perform runs inline, one round per step like one pass of the terminal loop: work that performs again runs at the next step, so a chain of performs takes one Harness::render per link and an endless one never blocks a test.

Implementations

impl<A: App> Harness<A>

pub fn new(app: A, width: u16, height: u16) -> Self

A harness with the built-in environment and a width × height screen, already rendered.

The first frame starts the application as the terminal runtime does: the size reaches App::resized, then App::init runs, so the focus it asks for is in place before the first simulated key.

pub fn with_env(app: A, env: Env, width: u16, height: u16) -> Self

A harness with a custom environment.

pub fn render(&mut self) -> &mut Self

Paints the current view.

pub fn send(&mut self, message: A::Msg) -> &mut Self

Delivers message to the application as if a widget had sent it, then renders.

pub fn press(&mut self, chord: &str) -> &mut Self

Presses a key chord such as "ctrl+s", "tab" or "?".

pub fn type_text(&mut self, text: &str) -> &mut Self

Types text one character at a time.

pub fn events(&mut self, events: &[Event]) -> &mut Self

Delivers events in order at the current clock time and renders once afterwards, the way the terminal loop handles every event waiting between two frames. Widgets see the later events with what the earlier ones changed but the rects of the frame before, e.g. a click where a submenu was drawn that a key delivered in the same call already closed.

pub fn paste(&mut self, text: &str) -> &mut Self

Pastes text.

pub fn click(&mut self, x: i32, y: i32) -> &mut Self

Clicks the left button on a cell.

pub fn click_text(&mut self, text: &str) -> &mut Self

Clicks the first cell of the first occurrence of text on screen.

Panics

Panics when text is not on screen.

pub fn drag(&mut self, from: (i32, i32), to: (i32, i32)) -> &mut Self

Presses the left button on from, drags to to and releases there.

pub fn hover(&mut self, x: i32, y: i32) -> &mut Self

Moves the pointer to a cell.

pub fn mouse(&mut self, kind: MouseKind, x: i32, y: i32) -> &mut Self

Sends a mouse event.

pub fn advance(&mut self, duration: Duration) -> &mut Self

Moves the fake clock forward and renders. Idleness moves with it: what View::idle_for reads grows by duration, and a View::on_idle watch whose silence is reached is told. Every simulated input (a key, the mouse, a paste) starts the silence again; send, resize and theme or language changes do not.

A termination whose Termination::grace is over by then quits, as it does in the runtime.

pub fn terminate(&mut self, cause: Termination) -> &mut Self

Simulates the signal behind cause, the way the terminal runtime hears a SIGTERM or a SIGHUP, then renders. The application hears it through App::terminating exactly as it would in a terminal, so a test can check its answer:

• An answer of None quits at once: Harness::quit_requested is true.
• A message is applied; the application stays until it quits or until Harness::advance moves the clock past Termination::grace.
• Calling this again with Termination::Terminate quits, as a second signal does. A repeated Termination::Hangup changes nothing, and one during a pending terminate is told to the application again.

The harness keeps drawing after a hangup, so a test can still read the screen; the runtime stops drawing, since the terminal is gone.

use qframe::prelude::*;
use qframe::runtime::Termination;

struct Editor;

impl App for Editor {
    type Msg = ();
    fn update(&mut self, (): ()) -> Command<()> {
        Command::none()
    }
    fn view(&self, ui: &mut View<'_, ()>) {
        ui.add(Text::new("notes.md"));
    }
}

// An application that implements nothing quits cleanly on either signal.
let mut app = Harness::new(Editor, 20, 3);
app.terminate(Termination::Terminate);
assert!(app.quit_requested());

pub fn key(&mut self, event: KeyEvent) -> &mut Self

Delivers a key event exactly as given, without moving the clock: a KeyKind::Repeat or KeyKind::Release from a terminal with the kitty keyboard protocol, or a press repeated by a held key.

pub fn set_theme(&mut self, id: &str) -> &mut Self

Switches theme, as Command::set_theme would.

pub fn set_locale(&mut self, code: &str) -> &mut Self

Switches language, as Command::set_locale would.

pub fn set_reduced_motion(&mut self, reduced: bool) -> &mut Self

Turns reduced motion on or off.

pub fn set_depth(&mut self, depth: ColorDepth) -> &mut Self

Draws as a terminal with depth colours would. Cells then carry palette indices instead of colours, which Harness::fg and Harness::bg cannot read; compare Harness::buffer cells for those.

pub fn set_glyph_mode(&mut self, mode: GlyphMode) -> &mut Self

Switches the glyph column drawn.

pub fn resize(&mut self, width: u16, height: u16) -> &mut Self

Resizes the screen to width × height and renders, as a terminal resize does in the runtime: the backend hands the engine a fresh, empty buffer of the new size and the next frame is drawn in full. A new size reaches App::resized before that frame is built.

pub fn screen(&self) -> String

The screen as text, one line per row, trailing spaces removed.

pub fn html(&self, caption: &str) -> String

The screen as a self-contained HTML fragment with colours and weights, for looking at renders in a browser. Wrap fragments with html_page to get a document.

pub fn find(&self, text: &str) -> Option<(i32, i32)>

Screen position of the first occurrence of text, in cells.

pub fn fg(&self, x: u16, y: u16) -> Option<Rgb>

Text colour of a cell.

Panics

Panics when the cell is outside the screen.

pub fn bg(&self, x: u16, y: u16) -> Option<Rgb>

Background colour of a cell.

Panics

Panics when the cell is outside the screen.

pub fn is_bold(&self, x: u16, y: u16) -> bool

Whether a cell is bold.

Panics

Panics when the cell is outside the screen.

pub fn buffer(&self) -> &Buffer

The rendered buffer.

pub fn app(&self) -> &A

The application.

pub fn env(&self) -> &Env

The environment.

pub fn copied(&self) -> &[String]

Texts copied to the clipboard so far.

pub fn clipboard(&self) -> Option<&str>

The in-process clipboard: the text copied last, if any.

pub fn set_system_clipboard(&mut self, text: Option<&str>) -> &mut Self

Stands in for the system clipboard that pasting reads first: Some text as if the user had copied it in another program, None for an empty clipboard (the start). A harness never reads the real clipboard or asks a terminal, so without this pasting uses the text the application copied last.

pub fn handoffs(&self) -> &[HandoffRequest]

The handoffs of Command::handoff the application asked for, oldest first. A harness has no terminal to hand over, so it records the request and answers it with the outcome of Harness::set_handoff_outcome instead of running the program.

pub fn set_handoff_outcome(&mut self, outcome: HandoffOutcome) -> &mut Self

The outcome every handoff from now on ends with; Finished { code: Some(0) } without this.

pub fn quit_requested(&self) -> bool

Whether the application asked to quit.

pub fn is_focused(&self, name: &str) -> bool

Whether the widget named name has keyboard focus.