[Python-checkins] bpo-36454: Fix test_time.test_monotonic() (GH-12929)

[Victor Stinner]

https://github.com/python/cpython/commit/d246a6766b9d8cc625112906299c4cb019944300
commit: d246a6766b9d8cc625112906299c4cb019944300
branch: master
author: Victor Stinner <vstinner at redhat.com>
committer: GitHub <noreply at github.com>
date: 2019-04-24T00:15:12+02:00
summary:

bpo-36454: Fix test_time.test_monotonic() (GH-12929)

Change test_time.test_monotonic() to test only the lower bound of elapsed time
after a sleep command rather than the upper bound. This prevents unnecessary
test failures on slow buildbots. Patch by Victor Stinner.

files:
A Misc/NEWS.d/next/Tests/2019-04-23-17-48-11.bpo-36454.0q4lQz.rst
M Lib/test/test_time.py

diff --git a/Lib/test/test_time.py b/Lib/test/test_time.py
index 303918960b63..42799b2a21ca 100644
--- a/Lib/test/test_time.py
+++ b/Lib/test/test_time.py
@@ -470,8 +470,9 @@ def test_monotonic(self):
         t2 = time.monotonic()
         dt = t2 - t1
         self.assertGreater(t2, t1)
-        # Issue #20101: On some Windows machines, dt may be slightly low
-        self.assertTrue(0.45 <= dt <= 1.0, dt)
+        # bpo-20101: tolerate a difference of 50 ms because of bad timer
+        # resolution on Windows
+        self.assertTrue(0.450 <= dt)
 
         # monotonic() is a monotonic but non adjustable clock
         info = time.get_clock_info('monotonic')
diff --git a/Misc/NEWS.d/next/Tests/2019-04-23-17-48-11.bpo-36454.0q4lQz.rst b/Misc/NEWS.d/next/Tests/2019-04-23-17-48-11.bpo-36454.0q4lQz.rst
new file mode 100644
index 000000000000..151c7ab04040
--- /dev/null
+++ b/Misc/NEWS.d/next/Tests/2019-04-23-17-48-11.bpo-36454.0q4lQz.rst
@@ -0,0 +1,3 @@
+Change test_time.test_monotonic() to test only the lower bound of elapsed time
+after a sleep command rather than the upper bound. This prevents unnecessary
+test failures on slow buildbots. Patch by Victor Stinner.