From 2c446658e56245a83d7c76c36aebfe0e8864c649 Mon Sep 17 00:00:00 2001
From: Syrus Akbary <me@syrusakbary.com>
Date: Sun, 7 Aug 2016 17:01:09 -0700
Subject: [PATCH] Improved tests

---
 .../graphene_sqlalchemy/registry.py           |  5 ++-
 graphene/relay/tests/test_node_custom.py      | 40 +++++++++++++++++--
 2 files changed, 41 insertions(+), 4 deletions(-)

diff --git a/graphene-sqlalchemy/graphene_sqlalchemy/registry.py b/graphene-sqlalchemy/graphene_sqlalchemy/registry.py
index e194529c..5062f1ab 100644
--- a/graphene-sqlalchemy/graphene_sqlalchemy/registry.py
+++ b/graphene-sqlalchemy/graphene_sqlalchemy/registry.py
@@ -7,7 +7,10 @@ class Registry(object):
         from .types import SQLAlchemyObjectType
         assert issubclass(cls, SQLAlchemyObjectType), 'Only SQLAlchemyObjectType can be registered, received "{}"'.format(cls.__name__)
         assert cls._meta.registry == self, 'Registry for a Model have to match.'
-        assert cls._meta.model not in self._registry, 'SQLAlchemy model "{}" already associated with another type "{}".'.format(cls._meta.model, self._registry[cls._meta.model])
+        assert self.get_type_for_model(cls._meta.model) in [None, cls], (
+            'SQLAlchemy model "{}" already associated with '
+            'another type "{}".'
+        ).format(cls._meta.model, self._registry[cls._meta.model])
         self._registry[cls._meta.model] = cls
 
     def get_type_for_model(self, model):
diff --git a/graphene/relay/tests/test_node_custom.py b/graphene/relay/tests/test_node_custom.py
index 73a17fc9..f6020381 100644
--- a/graphene/relay/tests/test_node_custom.py
+++ b/graphene/relay/tests/test_node_custom.py
@@ -1,6 +1,6 @@
 from graphql import graphql
 
-from ...types import ObjectType, Schema
+from ...types import ObjectType, Interface, Schema
 from ...types.scalars import Int, String
 from ..node import Node
 
@@ -20,12 +20,16 @@ class CustomNode(Node):
             return photo_data.get(id)
 
 
+class BasePhoto(Interface):
+    width = Int()
+
+
 class User(CustomNode, ObjectType):
     name = String()
 
 
-class Photo(CustomNode, ObjectType):
-    width = Int()
+class Photo(CustomNode, BasePhoto, ObjectType):
+    pass
 
 
 user_data = {
@@ -45,6 +49,36 @@ class RootQuery(ObjectType):
 schema = Schema(query=RootQuery, types=[User, Photo])
 
 
+def test_str_schema_correct():
+    print str(schema)
+    assert str(schema) == '''schema {
+  query: RootQuery
+}
+
+interface BasePhoto {
+  width: Int
+}
+
+interface Node {
+  id: ID!
+}
+
+type Photo implements Node, BasePhoto {
+  id: ID!
+  width: Int
+}
+
+type RootQuery {
+  node(id: ID!): Node
+}
+
+type User implements Node {
+  id: ID!
+  name: String
+}
+'''
+
+
 def test_gets_the_correct_id_for_users():
     query = '''
       {