egui_kittest

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

Example usage

use egui::accesskit::{Role, Toggled};
use egui::{CentralPanel, Context, TextEdit, Vec2};
use egui_kittest::Harness;
use kittest::Queryable;
use std::cell::RefCell;

fn main() {
    let mut checked = false;
    let app = |ctx: &Context| {
        CentralPanel::default().show(ctx, |ui| {
            ui.checkbox(&mut checked, "Check me!");
        });
    };

    let mut harness = Harness::builder().with_size(egui::Vec2::new(200.0, 100.0)).build(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));

    // You can even render the ui and do image snapshot tests
    #[cfg(all(feature = "wgpu", feature = "snapshot"))]
    harness.wgpu_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::wgpu_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 still cause the tests to fail, but on the next run, the tests should pass.

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