add test

Author: Rich-Harris

packages/svelte/tests/runtime-runes/samples/effect-untrack-teardown/_config.js

@@ -0,0 +1,4 @@
+import { test } from '../../test';
+
+// nothing to test here — if the teardown function is not untracked, effect will loop
+export default test({});

packages/svelte/tests/runtime-runes/samples/effect-untrack-teardown/main.svelte

@@ -0,0 +1,19 @@
+<script>
+	let prop = $state();
+	let key = $state({});
+
+	function action() {
+		prop = {};
+		$effect.pre(() => {
+			return () => {
+				prop;
+			}
+		});
+	}
+
+	$effect(() => key = {});
+</script>
+
+{#key key}
+	<div use:action>test</div>
+{/key}