I typically run the test suite with the “python -bWall” options enabled, and there is a new warning. I suspect it is a result of the DeprecationWarning upgrade in revision 5877c191b76e. When -Werror is enabled it causes test failure.

The fix is probably pretty easy; there are probably other deprecated modules tested in the test suite to copy from. I think there is a test.support function that can suppress deprecation warnings while importing a particular module.

$ make -s -j2 && LC_TIME= ./python -bWall -m test.regrtest -j0
. . .
[167/399] test_imp
/media/disk/home/proj/python/cpython/Lib/test/test_imp.py:16: DeprecationWarning: the imp module is deprecated in favour of importlib; see the module's documentation for alternative uses
  import imp
. . .
[207/399] test_modulefinder -- running: test_lzma (39 sec)
/media/disk/home/proj/python/cpython/Lib/modulefinder.py:14: DeprecationWarning: the imp module is deprecated in favour of importlib; see the module's documentation for alternative uses
  import imp
. . .
[335/399] test_threaded_import -- running: test_tarfile (36 sec), test_subprocess (62 sec)
/media/disk/home/proj/python/cpython/Lib/modulefinder.py:14: DeprecationWarning: the imp module is deprecated in favour of importlib; see the module's documentation for alternative uses
  import imp

New changeset 3f924cb4c3eb by Brett Cannon in branch 'default':
Issue #25487: Fix tests not updated when the imp module moved to a
https://hg.python.org/cpython/rev/3f924cb4c3eb

Thanks for the finding these, Martin!