add test

Author: trueadm

packages/svelte/src/reactivity/set.test.ts

@@ -106,3 +106,50 @@ test('set.forEach()', () => {
 
 	cleanup();
 });
+
+test('not invoking reactivity when value is not in the set after changes', () => {
+	const set = new ReactiveSet([1, 2]);
+
+	const log: any = [];
+
+	const cleanup = effect_root(() => {
+		render_effect(() => {
+			log.push('has 1', set.has(1));
+		});
+
+		render_effect(() => {
+			log.push('has 2', set.has(2));
+		});
+
+		render_effect(() => {
+			log.push('has 3', set.has(3));
+		});
+	});
+
+	flushSync(() => {
+		set.delete(2);
+	});
+
+	flushSync(() => {
+		set.add(2);
+	});
+
+	assert.deepEqual(log, [
+		'has 1',
+		true,
+		'has 2',
+		true,
+		'has 3',
+		false,
+		'has 2',
+		false,
+		'has 2',
+		true
+	]);
+
+	cleanup();
+});
+
+test('Set.instanceOf', () => {
+	assert.equal(new ReactiveSet() instanceof Set, true);
+});