egui/crates/egui_kittest

egui_kittest

Ui testing library for egui, based on kittest (an AccessKit based testing library).

Example usage

use egui::accesskit::Toggled;
use egui_kittest::{Harness, kittest::Queryable};

fn main() {
    let mut checked = false;
    let app = |ui: &mut egui::Ui| {
        ui.checkbox(&mut checked, "Check me!");
    };

    let mut harness = Harness::new_ui(app);

    let checkbox = harness.get_by_label("Check me!");
    assert_eq!(checkbox.toggled(), Some(Toggled::False));
    checkbox.click();

    harness.run();

    let checkbox = harness.get_by_label("Check me!");
    assert_eq!(checkbox.toggled(), Some(Toggled::True));

    // Shrink the window size to the smallest size possible
    harness.fit_contents();

    // You can even render the ui and do image snapshot tests
    #[cfg(all(feature = "wgpu", feature = "snapshot"))]
    harness.snapshot("readme_example");
}

Snapshot testing

There is a snapshot testing feature. To create snapshot tests, enable the snapshot and wgpu features. Once enabled, you can call Harness::snapshot to render the ui and save the image to the tests/snapshots directory.

To update the snapshots, run your tests with UPDATE_SNAPSHOTS=true, so e.g. UPDATE_SNAPSHOTS=true cargo test. Running with UPDATE_SNAPSHOTS=true will cause the tests to succeed. This is so that you can set UPDATE_SNAPSHOTS=true and update all tests, without cargo test failing on the first failing crate.

If you want to have multiple snapshots in the same test, it makes sense to collect the results in a Vec (look here for an example). This way they can all be updated at the same time.

You should add the following to your .gitignore:

**/tests/snapshots/**/*.diff.png
**/tests/snapshots/**/*.new.png