http://buildbot.python.org/all/#/builders/130/builds/87

======================================================================
FAIL: test_no_args_respects_force_flag (test.test_compileall.CommandLineTests)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "C:\buildbot.python.org\3.7.kloth-win64\build\lib\test\test_compileall.py", line 301, in test_no_args_respects_force_flag
    self.assertRunOK('-f', PYTHONPATH=self.directory)
  File "C:\buildbot.python.org\3.7.kloth-win64\build\lib\test\test_compileall.py", line 252, in assertRunOK
    *self._get_run_args(args), **env_vars)
  File "C:\buildbot.python.org\3.7.kloth-win64\build\lib\test\support\script_helper.py", line 157, in assert_python_ok
    return _assert_python(True, *args, **env_vars)
  File "C:\buildbot.python.org\3.7.kloth-win64\build\lib\test\support\script_helper.py", line 143, in _assert_python
    res.fail(cmd_line)
  File "C:\buildbot.python.org\3.7.kloth-win64\build\lib\test\support\script_helper.py", line 84, in fail
    err))
AssertionError: Process return code is 1
command line: ['C:\\buildbot.python.org\\3.7.kloth-win64\\build\\PCbuild\\amd64\\python_d.exe', '-X', 'faulthandler', '-S', '-m', 'compileall', '-f']

stdout:
---
(...)
Compiling 'C:\\buildbot.python.org\\3.7.kloth-win64\\build\\lib\\sndhdr.py'...
Compiling 'C:\\buildbot.python.org\\3.7.kloth-win64\\build\\lib\\socket.py'...
*** PermissionError: [WinError 5] Access is denied: 'C:\\buildbot.python.org\\3.7.kloth-win64\\build\\lib\\__pycache__\\socket.cpython-37.pyc.30129088' -> 'C:\\buildbot.python.org\\3.7.kloth-win64\\build\\lib\\__pycache__\\socket.cpython-37.pyc'
Compiling (...)
(...)
---

See also bpo-20760 which seems to be a duplicate but doesn't have the full output (stdout is missing).

#20760 reported failures on Linux.  I think one of these two issues should be closed.  FWIW, I ran
f:\dev\3x>python -m test -R 3:10 -m CommandLineTests test_compileall
twice with no failures.

While the issue is rare, I am sure that there is a race condition. The bug
maybe happens when other tests run in parallel.

The test should work in its own temporary directory to no be bothered by
other tests.