Added a unit test case for issue #11.

We added a case to check that callable return values of __getitem__
are not called.  There is already a test that callable attributes
are called: test_object__attribute_is_callable().

tests/test_context.py

@@ -69,6 +69,18 @@ class GetItemTestCase(TestCase):
         obj = {"foo": "bar"}
         self.assertEquals(_get_item(obj, "foo"), "bar")
 
+    def test_dictionary__callable_not_called(self):
+        """
+        Test that callable values are returned as-is (and in particular not called).
+
+        """
+        def foo_callable(self):
+            return "bar"
+
+        obj = {"foo": foo_callable}
+        self.assertNotEquals(_get_item(obj, "foo"), "bar")
+        self.assertTrue(_get_item(obj, "foo") is foo_callable)
+
     def test_dictionary__key_missing(self):
         """
         Test getting a missing key from a dictionary.