Cleanup exception class heirarchy and imports, make overriding the login failure…

Cleanup exception class heirarchy and imports, make overriding the login failure handler a settings option, add additional test cases to veryfiy that overriding the handler works and that the proper exceptions are being passed

README.txt

@@ -154,3 +154,15 @@ If your users should use a physical multi-factor authentication method, such as
 If the user's OpenID provider supports the PAPE extension and provides the Physical Multifactor authentication policy, this will
 cause the OpenID login to fail if the user does not provide valid physical authentication to the provider.
 
+== Override Login Failure Handling ==
+
+You can optionally provide your own handler for login failures by adding the following setting:
+
+        OPENID_RENDER_FAILURE = failure_handler_function
+
+Where failure_handler_function is a function reference that will take the following parameters:
+
+        def failure_handler_function(request, message, status=None, template_name=None, exception=None)
+
+This function must return a Django.http.HttpResponse instance.
+

django_openid_auth/auth.py

@@ -38,7 +38,6 @@ from openid.extensions import ax, sreg, pape
 from django_openid_auth import teams
 from django_openid_auth.models import UserOpenID
 from django_openid_auth.exceptions import (
-    DjangoOpenIDException,
     IdentityAlreadyClaimed,
     DuplicateUsernameViolation,
     MissingUsernameViolation,

django_openid_auth/exceptions.py

@@ -39,10 +39,7 @@ class IdentityAlreadyClaimed(DjangoOpenIDException):
         else:
             self.message = message
 
-class StrictUsernameViolation(DjangoOpenIDException):
-    pass
-    
-class DuplicateUsernameViolation(StrictUsernameViolation):
+class DuplicateUsernameViolation(DjangoOpenIDException):
 
     def __init__(self, message=None):
         if message is None:
@@ -50,7 +47,7 @@ class DuplicateUsernameViolation(StrictUsernameViolation):
         else:
             self.message = message
 
-class MissingUsernameViolation(StrictUsernameViolation):
+class MissingUsernameViolation(DjangoOpenIDException):
 
     def __init__(self, message=None):
         if message is None:

django_openid_auth/views.py

@@ -55,13 +55,7 @@ from django_openid_auth.forms import OpenIDLoginForm
 from django_openid_auth.models import UserOpenID
 from django_openid_auth.signals import openid_login_complete
 from django_openid_auth.store import DjangoOpenIDStore
-from django_openid_auth.exceptions import (
-    DjangoOpenIDException,
-    IdentityAlreadyClaimed,
-    DuplicateUsernameViolation,
-    MissingUsernameViolation,
-    MissingPhysicalMultiFactor,
-)
+from django_openid_auth.exceptions import DjangoOpenIDException
 
 
 next_url_re = re.compile('^/[-\w/]+$')
@@ -248,8 +242,11 @@ def login_begin(request, template_name='openid/login.html',
 
 @csrf_exempt
 def login_complete(request, redirect_field_name=REDIRECT_FIELD_NAME,
-                   render_failure=default_render_failure):
+                   render_failure=None):
     redirect_to = request.REQUEST.get(redirect_field_name, '')
+    render_failure = render_failure or \
+                     getattr(settings, 'OPENID_RENDER_FAILURE', None) or \
+                     default_render_failure
 
     openid_response = parse_openid_response(request)
     if not openid_response: