bpo-39056: Fix handling invalid warning category in the -W option. (GH-17618)

No longer import the re module if it is not needed.

1 files changed, 23 insertions, 0 deletions

diff --git a/Lib/test/test_warnings/__init__.py b/Lib/test/test_warnings/__init__.py
index 3a6d64eaad..c6fb097ae6 100644
--- a/Lib/test/test_warnings/__init__.py
+++ b/Lib/test/test_warnings/__init__.py
@@ -43,6 +43,10 @@ def warnings_state(module):
         module.filters = original_filters
 
 
+class TestWarning(Warning):
+    pass
+
+
 class BaseTest:
 
     """Basic bookkeeping required for testing."""
@@ -566,9 +570,28 @@ class WCmdLineTests(BaseTest):
                               self.module._setoption, 'bogus::Warning')
             self.assertRaises(self.module._OptionError,
                               self.module._setoption, 'ignore:2::4:-5')
+            with self.assertRaises(self.module._OptionError):
+                self.module._setoption('ignore::123')
+            with self.assertRaises(self.module._OptionError):
+                self.module._setoption('ignore::123abc')
+            with self.assertRaises(self.module._OptionError):
+                self.module._setoption('ignore::===')
+            with self.assertRaisesRegex(self.module._OptionError, 'Wärning'):
+                self.module._setoption('ignore::Wärning')
             self.module._setoption('error::Warning::0')
             self.assertRaises(UserWarning, self.module.warn, 'convert to error')
 
+    def test_import_from_module(self):
+        with original_warnings.catch_warnings(module=self.module):
+            self.module._setoption('ignore::Warning')
+            with self.assertRaises(self.module._OptionError):
+                self.module._setoption('ignore::TestWarning')
+            with self.assertRaises(self.module._OptionError):
+                self.module._setoption('ignore::test.test_warnings.bogus')
+            self.module._setoption('error::test.test_warnings.TestWarning')
+            with self.assertRaises(TestWarning):
+                self.module.warn('test warning', TestWarning)
+
 
 class CWCmdLineTests(WCmdLineTests, unittest.TestCase):
     module = c_warnings