bpo-33723: Remove busy loop from test_time (GH-10773)

The "busy loops" of test_process_time() and test_thread_time() are
not reliable and fail randomly on Windows: remove them.

Author: vstinner

Lib/test/test_time.py

@@ -46,12 +46,6 @@ class _PyTime(enum.IntEnum):
 )
 
 
-def busy_wait(duration):
-    deadline = time.monotonic() + duration
-    while time.monotonic() < deadline:
-        pass
-
-
 class TimeTestCase(unittest.TestCase):
 
     def setUp(self):
@@ -495,25 +489,6 @@ def test_process_time(self):
         # on Windows
         self.assertLess(stop - start, 0.020)
 
-        # bpo-33723: A busy loop of 100 ms should increase process_time()
-        # by at least 15 ms. Tolerate 15 ms because of the bad resolution of
-        # the clock on Windows (around 15.6 ms).
-        min_time = 0.015
-        busy_time = 0.100
-
-        # process_time() should include CPU time spent in any thread
-        start = time.process_time()
-        busy_wait(busy_time)
-        stop = time.process_time()
-        self.assertGreaterEqual(stop - start, min_time)
-
-        t = threading.Thread(target=busy_wait, args=(busy_time,))
-        start = time.process_time()
-        t.start()
-        t.join()
-        stop = time.process_time()
-        self.assertGreaterEqual(stop - start, min_time)
-
         info = time.get_clock_info('process_time')
         self.assertTrue(info.monotonic)
         self.assertFalse(info.adjustable)
@@ -534,28 +509,6 @@ def test_thread_time(self):
         # on Windows
         self.assertLess(stop - start, 0.020)
 
-        # bpo-33723: A busy loop of 100 ms should increase thread_time()
-        # by at least 15 ms, but less than 30 ms in other threads.
-        # Tolerate 15 and 30 ms because of the bad resolution
-        # of the clock on Windows (around 15.6 ms).
-        min_time = 0.015
-        max_time = 0.030
-        busy_time = 0.100
-
-        # thread_time() should include CPU time spent in current thread...
-        start = time.thread_time()
-        busy_wait(busy_time)
-        stop = time.thread_time()
-        self.assertGreaterEqual(stop - start, min_time)
-
-        # ...but not in other threads
-        t = threading.Thread(target=busy_wait, args=(busy_time,))
-        start = time.thread_time()
-        t.start()
-        t.join()
-        stop = time.thread_time()
-        self.assertLess(stop - start, max_time)
-
         info = time.get_clock_info('thread_time')
         self.assertTrue(info.monotonic)
         self.assertFalse(info.adjustable)