Pressability: Eliminate Unit Test Timing Flakiness

Summary:
Currently, it is possible in one of the "minimum press duration" unit tests for certain instructions to take longer than expected, skewing the return value of `Date.now()` by at least 10ms.

This changes the unit test to mock `Date.now()` more accurately so that the test is no longer flakey.

Changelog: [Internal]

Reviewed By: jacdebug

Differential Revision: D39804152

fbshipit-source-id: ab62fd1921bd015d969da9595bd3267c38c6e59c

Libraries/Pressability/__tests__/Pressability-test.js

@@ -233,6 +233,7 @@ const createMockPressEvent = (
 describe('Pressability', () => {
   beforeEach(() => {
     jest.resetModules();
+    jest.restoreAllMocks();
     jest.spyOn(Date, 'now');
     jest.spyOn(HoverState, 'isHoverEnabled');
   });
@@ -667,15 +668,20 @@ describe('Pressability', () => {
       handlers.onResponderMove(createMockPressEvent('onResponderMove'));
       jest.runOnlyPendingTimers();
       expect(config.onPressIn).toBeCalled();
+
       // WORKAROUND: Jest does not advance `Date.now()`.
-      const touchActivateTime = Date.now();
+      expect(Date.now).toHaveBeenCalledTimes(1);
+      const touchActivateTime = Date.now.mock.results[0].value;
       jest.advanceTimersByTime(120);
       Date.now.mockReturnValue(touchActivateTime + 120);
       handlers.onResponderRelease(createMockPressEvent('onResponderRelease'));
 
       expect(config.onPressOut).not.toBeCalled();
       jest.advanceTimersByTime(10);
+      Date.now.mockReturnValue(touchActivateTime + 130);
       expect(config.onPressOut).toBeCalled();
+
+      Date.now.mockRestore();
     });
 
     it('is called synchronously if minimum press duration is 0ms', () => {