SF patch #667730: More DictMixin

* Adds missing pop() methods to weakref.py
* Expands test suite to broaden coverage of objects with
  a mapping interface.

Contributed by Sebastien Keim.

Lib/test/test_os.py

@@ -185,10 +185,28 @@ class StatAttributeTests(unittest.TestCase):
         except TypeError:
             pass
 
+from test_userdict import TestMappingProtocol
+
+class EnvironTests(TestMappingProtocol):
+    """check that os.environ object conform to mapping protocol"""
+    _tested_class = None
+    def _reference(self):
+        return {"KEY1":"VALUE1", "KEY2":"VALUE2", "KEY3":"VALUE3"}
+    def _empty_mapping(self):
+        os.environ.clear()
+        return os.environ
+    def setUp(self):
+        self.__save = dict(os.environ)
+        os.environ.clear()
+    def tearDown(self):
+        os.environ.clear()
+        os.environ.update(self.__save)
+
 def test_main():
     suite = unittest.TestSuite()
     suite.addTest(unittest.makeSuite(TemporaryFileTests))
     suite.addTest(unittest.makeSuite(StatAttributeTests))
+    suite.addTest(unittest.makeSuite(EnvironTests))
     run_suite(suite)
 
 if __name__ == "__main__":