try this

packages/svelte/tests/runtime-runes/samples/get-abort-signal/_config.js

@@ -6,11 +6,11 @@ export default test({
 	async test({ assert, target }) {
 		const [button] = target.querySelectorAll('button');
 
-		await new Promise((f) => setTimeout(f)); // TODO replace with `tick` once `await` lands
+		await new Promise((f) => setTimeout(f, 50)); // TODO replace with `tick` once `await` lands
 		assert.htmlEqual(target.innerHTML, '<button>increment</button><p>0</p>');
 
 		button.click();
-		await new Promise((f) => setTimeout(f)); // TODO replace with `tick` once `await` lands
+		await new Promise((f) => setTimeout(f, 50)); // TODO replace with `tick` once `await` lands
 		assert.htmlEqual(target.innerHTML, '<button>increment</button><p>2</p>');
 	}
 });