Add test for MemoryInfo (#53052)

Summary:
Pull Request resolved: #53052

Changelog: [internal]

Adds a test for `performance.memory`.

Reviewed By: hoxyq

Differential Revision: D79633246

fbshipit-source-id: 8f9df0219de6c04c8be75af4c9d03576a8164ea9

Author: rubennorte

packages/react-native/src/private/webapis/performance/__tests__/PerformanceMemory-itest.js

@@ -0,0 +1,28 @@
+/**
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @flow strict-local
+ * @format
+ */
+
+import type Performance from '../Performance';
+
+import '@react-native/fantom/src/setUpDefaultReactNativeEnvironment';
+
+declare var performance: Performance;
+
+describe('performance.memory', () => {
+  it('provides memory info', () => {
+    const memoryInfo = performance.memory;
+
+    expect(memoryInfo.usedJSHeapSize).toBeGreaterThan(0);
+    expect(memoryInfo.totalJSHeapSize).toBeGreaterThan(0);
+  });
+
+  it('always returns a new object', () => {
+    expect(performance.memory).not.toBe(performance.memory);
+  });
+});