Make test_sleep_until a little more tolerant

Author: haukex

Lib/test/test_time.py

@@ -164,7 +164,12 @@ def test_sleep_until(self):
         deadline = start + 2
         time.sleep_until(deadline)
         stop = time.time()
-        self.assertLess(abs(stop - deadline), 0.050)
+        delta = stop - deadline
+        # cargo-cult these 50ms from test_monotonic (bpo-20101)
+        self.assertGreater(delta, -0.050)
+        # allow sleep_until to take up to 1s longer than planned
+        # (e.g. in case the system is under heavy load during testing)
+        self.assertLess(delta, 1.000)
 
     def test_epoch(self):
         # bpo-43869: Make sure that Python use the same Epoch on all platforms: