diff --git a/graphene/types/tests/test_objecttype.py b/graphene/types/tests/test_objecttype.py
index 2acb578f..d2ae4ade 100644
--- a/graphene/types/tests/test_objecttype.py
+++ b/graphene/types/tests/test_objecttype.py
@@ -7,6 +7,7 @@ from ..scalars import String
 from ..schema import Schema
 from ..structures import NonNull
 from ..unmountedtype import UnmountedType
+import re
 
 
 class MyType(Interface):
@@ -228,11 +229,13 @@ def test_objecttype_with_possible_types_and_is_type_of_should_raise():
             def is_type_of(cls, root, context, info):
                 return False
 
-    assert str(excinfo.value) == (
-        "MyObjectType.Meta.possible_types will cause type collision with "
-        "MyObjectType.is_type_of. Please use one or other."
-    )
-
+    assertion_message = '''
+        MyObjectType.Meta.possible_types will cause type collision with MyObjectType.is_type_of.
+        Please use one or other.
+    '''
+    space_removed_excinfo = str(excinfo.value).replace(" ", "")
+    space_removed_assertion_message = assertion_message.replace(" ", "")
+    assert space_removed_assertion_message == space_removed_excinfo
 
 def test_objecttype_no_fields_output():
     class User(ObjectType):
diff --git a/graphene/types/typemap.py b/graphene/types/typemap.py
index f79dae6f..b0aca624 100644
--- a/graphene/types/typemap.py
+++ b/graphene/types/typemap.py
@@ -264,10 +264,10 @@ class TypeMap(GraphQLTypeMap):
             for objecttype in type._meta.types:
                 self.graphene_reducer(map, objecttype)
                 internal_type = map[objecttype._meta.name]
-                if internal_type.graphql_type != objecttype:
+                if internal_type.graphene_type != objecttype:
                     raise AssertionError(
                         "Found different types with the same name in the schema: {}, {}."
-                        .format(internal_type.graphql_type, objecttype)
+                        .format(internal_type.graphene_type, objecttype)
                     )
                 union_types.append(internal_type)
             return union_types
diff --git a/graphene/utils/subclass_with_meta.py b/graphene/utils/subclass_with_meta.py
index 01fc5375..b6dc0553 100644
--- a/graphene/utils/subclass_with_meta.py
+++ b/graphene/utils/subclass_with_meta.py
@@ -42,10 +42,14 @@ class SubclassWithMeta(six.with_metaclass(SubclassWithMeta_Meta)):
 
         abstract = options.pop("abstract", False)
         if abstract:
-            assert not options, (
-                "Abstract types can only contain the abstract attribute. "
-                "Received: abstract, {option_keys}"
-            ).format(option_keys=", ".join(options.keys()))
+            if options:
+                raise AssertionError(
+                    '''
+                       Abstract types can only contain the abstract attribute.
+                       Received: abstract, {option_keys}
+                    '''
+                    .format(option_keys=', '.join(options.keys()))
+                )
         else:
             super_class = super(cls, cls)
             if hasattr(super_class, "__init_subclass_with_meta__"):