Adds a script testing for bug 23058

http://bugs.python.org/issue23058

scripts/test_bug_23058.py

@@ -0,0 +1,57 @@
+from __future__ import unicode_literals
+
+import argparse
+import unittest
+
+
+class Test23058(unittest.TestCase):
+    def do_test_verbosity(self, parser, line, expected_verbosity):
+        try:
+            args = parser.parse_args(line.split())
+        except SystemExit:
+            self.fail("Parsing arguments failed")
+        self.assertEqual(args.verbosity, expected_verbosity)
+
+    def test_parents(self):
+        options = argparse.ArgumentParser(add_help=False)
+        options.add_argument('-v', '--verbose', action='count', default=1,
+                             dest='verbosity')
+
+        parser = argparse.ArgumentParser(parents=[options])
+
+        subparsers = parser.add_subparsers()
+
+        command = subparsers.add_parser('command', parents=[options])
+
+        self.do_test_verbosity(parser, 'command', 1)
+        self.do_test_verbosity(parser, 'command -v', 2)
+        self.do_test_verbosity(parser, 'command -v -v', 3)
+        self.do_test_verbosity(parser, '-v command', 2)  # FAILS
+                # arguments passed to main parser are *silently ignored*
+        self.do_test_verbosity(parser, '-v -v command', 3)
+        self.do_test_verbosity(parser, '-v -v command -v -v', 5)
+
+    def test_function(self):
+        def add_options(prs):
+            prs.add_argument('-v', '--verbose', action='count', default=1,
+                             dest='verbosity')
+
+        parser = argparse.ArgumentParser()
+        add_options(parser)
+
+        subparsers = parser.add_subparsers()
+
+        command = subparsers.add_parser('command')
+        add_options(command)
+
+        self.do_test_verbosity(parser, 'command', 1)
+        self.do_test_verbosity(parser, 'command -v', 2)
+        self.do_test_verbosity(parser, 'command -v -v', 3)
+        self.do_test_verbosity(parser, '-v command', 2)  # FAILS
+                # arguments passed to main parser are *silently ignored*
+        self.do_test_verbosity(parser, '-v -v command', 3)
+        self.do_test_verbosity(parser, '-v -v command -v -v', 5)
+
+
+if __name__ == '__main__':
+    unittest.main()