diff --git a/keystone/exception.py b/keystone/exception.py
index f1651bf008..84f1e79e13 100644
--- a/keystone/exception.py
+++ b/keystone/exception.py
@@ -107,12 +107,6 @@ class Conflict(Error):
     title = 'Conflict'
 
 
-class NotImplemented(Error):
-    """The action you have requested has not been implemented."""
-    code = 501
-    action = 'Not Implemented'
-
-
 class UnexpectedError(Error):
     """An unexpected error prevented the server from fulfilling your request.
 
@@ -121,3 +115,9 @@ class UnexpectedError(Error):
     """
     code = 500
     title = 'Internal Server Error'
+
+
+class NotImplemented(Error):
+    """The action you have requested has not been implemented."""
+    code = 501
+    title = 'Not Implemented'
diff --git a/tests/test_exception.py b/tests/test_exception.py
index a51efff2ca..c74a60c6c5 100644
--- a/tests/test_exception.py
+++ b/tests/test_exception.py
@@ -42,6 +42,20 @@ class ExceptionTestCase(test.TestCase):
         self.assertNotIn('  ', j['error']['message'])
         self.assertTrue(type(j['error']['code']) is int)
 
+    def test_all_json_renderings(self):
+        """Everything callable in the exception module should be renderable.
+
+        ... except for the base error class (exception.Error), which is not
+        user-facing.
+
+        This test provides a custom message to bypass docstring parsing, which
+        should be tested seperately.
+
+        """
+        for cls in [x for x in exception.__dict__.values() if callable(x)]:
+            if cls is not exception.Error:
+                self.assertValidJsonRendering(cls(message='Overriden.'))
+
     def test_validation_error(self):
         target = uuid.uuid4().hex
         attribute = uuid.uuid4().hex
@@ -50,10 +64,6 @@ class ExceptionTestCase(test.TestCase):
         self.assertIn(target, str(e))
         self.assertIn(attribute, str(e))
 
-    def test_unauthorized(self):
-        e = exception.Unauthorized()
-        self.assertValidJsonRendering(e)
-
     def test_forbidden_action(self):
         action = uuid.uuid4().hex
         e = exception.ForbiddenAction(action=action)