bpo-40055: test_distutils leaves warnings filters unchanged (GH-20095)

distutils.tests now saves/restores warnings filters to leave them unchanged. Importing tests imports docutils which imports pkg_resources which adds a warnings filter. (cherry picked from commit 6e57237) Co-authored-by: Victor Stinner <[email protected]>
python · May 15, 2020 · 4e6545b · 4e6545b
1 parent 07bd5cf
commit 4e6545b
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diff --git a/Lib/distutils/tests/__init__.py b/Lib/distutils/tests/__init__.py
@@ -15,20 +15,26 @@
 import os
 import sys
 import unittest
+import warnings
 from test.support import run_unittest
 
 
 here = os.path.dirname(__file__) or os.curdir
 
 
 def test_suite():
+    old_filters = warnings.filters[:]
     suite = unittest.TestSuite()
     for fn in os.listdir(here):
         if fn.startswith("test") and fn.endswith(".py"):
             modname = "distutils.tests." + fn[:-3]
             __import__(modname)
             module = sys.modules[modname]
             suite.addTest(module.test_suite())
+    # bpo-40055: Save/restore warnings filters to leave them unchanged.
+    # Importing tests imports docutils which imports pkg_resources which adds a
+    # warnings filter.
+    warnings.filters[:] = old_filters
     return suite
 
 

diff --git a/Misc/NEWS.d/next/Tests/2020-05-15-01-21-44.bpo-40055.Xp4aP9.rst b/Misc/NEWS.d/next/Tests/2020-05-15-01-21-44.bpo-40055.Xp4aP9.rst
@@ -0,0 +1,3 @@
+distutils.tests now saves/restores warnings filters to leave them unchanged.
+Importing tests imports docutils which imports pkg_resources which adds a
+warnings filter.