Reorganize tests for PerformanceObserver and User Timing API (#52587)

Summary:
Pull Request resolved: #52587

Changelog: [internal]

This just re-organizes the tests for the `Performance` API and `PerformanceObserver` as the previous organization didn't make much sense. Now it's a test for `PerformanceObserver` and another for the User Timing API.

Reviewed By: huntie

Differential Revision: D78193070

fbshipit-source-id: f15524bf07d2dc9edc155214279ce3af705cde67

Author: rubennorte

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

@@ -0,0 +1,109 @@
+/**
+ * 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 '@react-native/fantom/src/setUpDefaultReactNativeEnvironment';
+
+import type Performance from '../Performance';
+import type {
+  PerformanceObserver as PerformanceObserverT,
+  PerformanceObserverEntryList,
+} from '../PerformanceObserver';
+
+import setUpPerformanceObserver from '../../../setup/setUpPerformanceObserver';
+import * as Fantom from '@react-native/fantom';
+
+setUpPerformanceObserver();
+
+declare var performance: Performance;
+declare var PerformanceObserver: Class<PerformanceObserverT>;
+
+describe('PerformanceObserver', () => {
+  it('receives notifications for marks and measures', () => {
+    const callback = jest.fn();
+    const observer = new PerformanceObserver(callback);
+    observer.observe({entryTypes: ['mark', 'measure']});
+
+    expect(callback).not.toHaveBeenCalled();
+
+    let mark1;
+    let mark2;
+    let measure1;
+    let measure2;
+
+    Fantom.runTask(() => {
+      mark1 = performance.mark('mark1', {startTime: 20});
+      mark2 = performance.mark('mark2', {startTime: 10});
+      measure1 = performance.measure('measure1', {
+        start: 50,
+        duration: 20,
+      });
+      measure2 = performance.measure('measure2', {
+        start: 15,
+        duration: 10,
+      });
+
+      // The notification should be dispatched asynchronously.
+      expect(callback).not.toHaveBeenCalled();
+
+      Fantom.scheduleTask(() => {
+        // The notification should be dispatched with a low priority.
+        expect(callback).not.toHaveBeenCalled();
+      });
+    });
+
+    expect(callback).toHaveBeenCalledTimes(1);
+
+    const entries: PerformanceObserverEntryList = callback.mock.calls[0][0];
+
+    // Sorted by startTime.
+    expect(entries.getEntries()).toEqual([mark2, measure2, mark1, measure1]);
+
+    // Sorted by startTime.
+    expect(entries.getEntriesByName('mark1')).toEqual([mark1]);
+
+    // Sorted by startTime.
+    expect(entries.getEntriesByType('mark')).toEqual([mark2, mark1]);
+
+    expect(callback.mock.calls[0][1]).toBe(observer);
+  });
+
+  // eslint-disable-next-line jest/no-disabled-tests
+  it.skip('provides the same performance entry references from mark/measure to all observers', () => {
+    const callback1 = jest.fn();
+    const callback2 = jest.fn();
+    const observer1 = new PerformanceObserver(callback1);
+    const observer2 = new PerformanceObserver(callback2);
+    observer1.observe({entryTypes: ['mark', 'measure']});
+    observer2.observe({entryTypes: ['mark', 'measure']});
+
+    let mark;
+    let measure;
+
+    Fantom.runTask(() => {
+      mark = performance.mark('mark', {startTime: 20});
+      measure = performance.measure('measure', {
+        start: 25,
+        duration: 10,
+      });
+    });
+
+    expect(callback1).toHaveBeenCalledTimes(1);
+    expect(callback2).toHaveBeenCalledTimes(1);
+
+    const entries1: PerformanceObserverEntryList = callback1.mock.calls[0][0];
+    const entries2: PerformanceObserverEntryList = callback2.mock.calls[0][0];
+
+    expect(entries1.getEntries()[0]).toBe(mark);
+    expect(entries2.getEntries()[0]).toBe(mark);
+
+    expect(entries1.getEntries()[1]).toBe(measure);
+    expect(entries2.getEntries()[1]).toBe(measure);
+  });
+});

packages/react-native/src/private/webapis/performance/__tests__/Performance-itest.js renamed to packages/react-native/src/private/webapis/performance/__tests__/UserTiming-itest.js

@@ -36,7 +36,7 @@ function toJSON(entries: PerformanceEntryList): Array<PerformanceEntryJSON> {
   return entries.map(entry => entry.toJSON());
 }
 
-describe('Performance', () => {
+describe('User Timing', () => {
   beforeEach(() => {
     performance.clearMarks();
     performance.clearMeasures();