svelte/test/runtime/samples/transition-inert/_config.js

export default {
	async test({ assert, component, target, raf }) {
		// jsdom doesn't set the inert attribute, and the transition checks if it exists, so set it manually to trigger the inert logic
		target.querySelector('button.a').inert = false;
		target.querySelector('button.b').inert = false;

		// check and abort halfway through the outro transition
		component.visible = false;
		raf.tick(50);
		assert.strictEqual(target.querySelector('button.a').inert, true);
		assert.strictEqual(target.querySelector('button.b').inert, true);

		component.visible = true;
		assert.strictEqual(target.querySelector('button.a').inert, false);
		assert.strictEqual(target.querySelector('button.b').inert, false);

		// let it transition out completely and then back in
		component.visible = false;
		raf.tick(101);
		component.visible = true;
		raf.tick(50);
		assert.strictEqual(target.querySelector('button.a').inert, false);
		assert.strictEqual(target.querySelector('button.b').inert, false);
		raf.tick(51);
		assert.strictEqual(target.querySelector('button.a').inert, false);
		assert.strictEqual(target.querySelector('button.b').inert, false);
	}
};