diff --git a/tests/fields.py b/tests/fields.py
index 5602cdec..d36a0804 100644
--- a/tests/fields.py
+++ b/tests/fields.py
@@ -523,29 +523,29 @@ class FieldTest(unittest.TestCase):
         Link.drop_collection()
         Post.drop_collection()
         Bookmark.drop_collection()
-    
+
         link_1 = Link(title="Pitchfork")
         link_1.save()
-    
+
         post_1 = Post(title="Behind the Scenes of the Pavement Reunion")
         post_1.save()
-        
+
         bm = Bookmark(bookmark_object=post_1)
         bm.save()
-        
+
         bm = Bookmark.objects(bookmark_object=post_1).first()
-        
+
         self.assertEqual(bm.bookmark_object, post_1)
         self.assertTrue(isinstance(bm.bookmark_object, Post))
-        
+
         bm.bookmark_object = link_1
         bm.save()
-        
+
         bm = Bookmark.objects(bookmark_object=link_1).first()
-        
+
         self.assertEqual(bm.bookmark_object, link_1)
         self.assertTrue(isinstance(bm.bookmark_object, Link))
-    
+
         Link.drop_collection()
         Post.drop_collection()
         Bookmark.drop_collection()
@@ -555,23 +555,23 @@ class FieldTest(unittest.TestCase):
         """
         class Link(Document):
             title = StringField()
-    
+
         class Post(Document):
             title = StringField()
-    
+
         class User(Document):
             bookmarks = ListField(GenericReferenceField())
-    
+
         Link.drop_collection()
         Post.drop_collection()
         User.drop_collection()
-    
+
         link_1 = Link(title="Pitchfork")
         link_1.save()
-    
+
         post_1 = Post(title="Behind the Scenes of the Pavement Reunion")
         post_1.save()
-    
+
         user = User(bookmarks=[post_1, link_1])
         user.save()