clean up document instance tests

tests/document/instance.py

@@ -28,8 +28,6 @@ TEST_IMAGE_PATH = os.path.join(os.path.dirname(__file__),
 __all__ = ("InstanceTest",)
 
 
-
-
 class InstanceTest(unittest.TestCase):
 
     def setUp(self):
@@ -72,8 +70,7 @@ class InstanceTest(unittest.TestCase):
             self.assertEqual(field._instance, instance)
 
     def test_capped_collection(self):
-        """Ensure that capped collections work properly.
+        """Ensure that capped collections work properly."""
-        """
         class Log(Document):
             date = DateTimeField(default=datetime.now)
             meta = {
@@ -181,8 +178,7 @@ class InstanceTest(unittest.TestCase):
         self.assertEqual('<Article: привет мир>', repr(doc))
 
     def test_repr_none(self):
-        """Ensure None values handled correctly
+        """Ensure None values are handled correctly."""
-        """
         class Article(Document):
             title = StringField()
 
@@ -190,25 +186,23 @@ class InstanceTest(unittest.TestCase):
                 return None
 
         doc = Article(title=u'привет мир')
-
         self.assertEqual('<Article: None>', repr(doc))
 
     def test_queryset_resurrects_dropped_collection(self):
         self.Person.drop_collection()
-
         self.assertEqual([], list(self.Person.objects()))
 
+        # Ensure works correctly with inhertited classes
         class Actor(self.Person):
             pass
 
-        # Ensure works correctly with inhertited classes
         Actor.objects()
         self.Person.drop_collection()
         self.assertEqual([], list(Actor.objects()))
 
     def test_polymorphic_references(self):
-        """Ensure that the correct subclasses are returned from a query when
+        """Ensure that the correct subclasses are returned from a query
-        using references / generic references
+        when using references / generic references
         """
         class Animal(Document):
             meta = {'allow_inheritance': True}
@@ -258,9 +252,6 @@ class InstanceTest(unittest.TestCase):
         classes = [a.__class__ for a in Zoo.objects.first().animals]
         self.assertEqual(classes, [Animal, Fish, Mammal, Dog, Human])
 
-        Zoo.drop_collection()
-        Animal.drop_collection()
-
     def test_reference_inheritance(self):
         class Stats(Document):
             created = DateTimeField(default=datetime.now)
@@ -287,8 +278,7 @@ class InstanceTest(unittest.TestCase):
         self.assertEqual(list_stats, CompareStats.objects.first().stats)
 
     def test_db_field_load(self):
-        """Ensure we load data correctly
+        """Ensure we load data correctly from the right db field."""
-        """
         class Person(Document):
             name = StringField(required=True)
             _rank = StringField(required=False, db_field="rank")
@@ -307,8 +297,7 @@ class InstanceTest(unittest.TestCase):
         self.assertEqual(Person.objects.get(name="Fred").rank, "Private")
 
     def test_db_embedded_doc_field_load(self):
-        """Ensure we load embedded document data correctly
+        """Ensure we load embedded document data correctly."""
-        """
         class Rank(EmbeddedDocument):
             title = StringField(required=True)
 
@@ -333,8 +322,7 @@ class InstanceTest(unittest.TestCase):
         self.assertEqual(Person.objects.get(name="Fred").rank, "Private")
 
     def test_custom_id_field(self):
-        """Ensure that documents may be created with custom primary keys.
+        """Ensure that documents may be created with custom primary keys."""
-        """
         class User(Document):
             username = StringField(primary_key=True)
             name = StringField()
@@ -382,10 +370,7 @@ class InstanceTest(unittest.TestCase):
         self.assertEqual(user_son['_id'], 'mongo')
         self.assertTrue('username' not in user_son['_id'])
 
-        User.drop_collection()
-
     def test_document_not_registered(self):
-
         class Place(Document):
             name = StringField()
 
@@ -407,7 +392,6 @@ class InstanceTest(unittest.TestCase):
             list(Place.objects.all())
 
     def test_document_registry_regressions(self):
-
         class Location(Document):
             name = StringField()
             meta = {'allow_inheritance': True}
@@ -421,18 +405,16 @@ class InstanceTest(unittest.TestCase):
         self.assertEqual(Area, get_document("Location.Area"))
 
     def test_creation(self):
-        """Ensure that document may be created using keyword arguments.
+        """Ensure that document may be created using keyword arguments."""
-        """
         person = self.Person(name="Test User", age=30)
         self.assertEqual(person.name, "Test User")
         self.assertEqual(person.age, 30)
 
     def test_to_dbref(self):
-        """Ensure that you can get a dbref of a document"""
+        """Ensure that you can get a dbref of a document."""
         person = self.Person(name="Test User", age=30)
         self.assertRaises(OperationError, person.to_dbref)
         person.save()
-
         person.to_dbref()
 
     def test_save_abstract_document(self):
@@ -445,8 +427,7 @@ class InstanceTest(unittest.TestCase):
             Doc(name='aaa').save()
 
     def test_reload(self):
-        """Ensure that attributes may be reloaded.
+        """Ensure that attributes may be reloaded."""
-        """
         person = self.Person(name="Test User", age=20)
         person.save()
 
@@ -479,7 +460,6 @@ class InstanceTest(unittest.TestCase):
         doc = Animal(superphylum='Deuterostomia')
         doc.save()
         doc.reload()
-        Animal.drop_collection()
 
     def test_reload_sharded_nested(self):
         class SuperPhylum(EmbeddedDocument):
@@ -493,11 +473,9 @@ class InstanceTest(unittest.TestCase):
         doc = Animal(superphylum=SuperPhylum(name='Deuterostomia'))
         doc.save()
         doc.reload()
-        Animal.drop_collection()
 
     def test_reload_referencing(self):
-        """Ensures reloading updates weakrefs correctly
+        """Ensures reloading updates weakrefs correctly."""
-        """
         class Embedded(EmbeddedDocument):
             dict_field = DictField()
             list_field = ListField()
@@ -569,8 +547,7 @@ class InstanceTest(unittest.TestCase):
             self.assertFalse("Threw wrong exception")
 
     def test_reload_of_non_strict_with_special_field_name(self):
-        """Ensures reloading works for documents with meta strict == False
+        """Ensures reloading works for documents with meta strict == False."""
-        """
         class Post(Document):
             meta = {
                 'strict': False
@@ -591,8 +568,7 @@ class InstanceTest(unittest.TestCase):
         self.assertEqual(post.items, ["more lorem", "even more ipsum"])
 
     def test_dictionary_access(self):
-        """Ensure that dictionary-style field access works properly.
+        """Ensure that dictionary-style field access works properly."""
-        """
         person = self.Person(name='Test User', age=30, job=self.Job())
         self.assertEqual(person['name'], 'Test User')
 
@@ -634,8 +610,7 @@ class InstanceTest(unittest.TestCase):
         self.assertEqual(sub_doc.to_mongo().keys(), ['id'])
 
     def test_embedded_document(self):
-        """Ensure that embedded documents are set up correctly.
+        """Ensure that embedded documents are set up correctly."""
-        """
         class Comment(EmbeddedDocument):
             content = StringField()
 
@@ -643,8 +618,7 @@ class InstanceTest(unittest.TestCase):
         self.assertFalse('id' in Comment._fields)
 
     def test_embedded_document_instance(self):
-        """Ensure that embedded documents can reference parent instance
+        """Ensure that embedded documents can reference parent instance."""
-        """
         class Embedded(EmbeddedDocument):
             string = StringField()
 
@@ -652,6 +626,7 @@ class InstanceTest(unittest.TestCase):
             embedded_field = EmbeddedDocumentField(Embedded)
 
         Doc.drop_collection()
+
         doc = Doc(embedded_field=Embedded(string="Hi"))
         self.assertHasInstance(doc.embedded_field, doc)
 
@@ -661,7 +636,8 @@ class InstanceTest(unittest.TestCase):
 
     def test_embedded_document_complex_instance(self):
         """Ensure that embedded documents in complex fields can reference
-        parent instance"""
+        parent instance.
+        """
         class Embedded(EmbeddedDocument):
             string = StringField()
 
@@ -677,8 +653,7 @@ class InstanceTest(unittest.TestCase):
         self.assertHasInstance(doc.embedded_field[0], doc)
 
     def test_embedded_document_complex_instance_no_use_db_field(self):
-        """Ensure that use_db_field is propagated to list of Emb Docs
+        """Ensure that use_db_field is propagated to list of Emb Docs."""
-        """
         class Embedded(EmbeddedDocument):
             string = StringField(db_field='s')
 
@@ -690,7 +665,6 @@ class InstanceTest(unittest.TestCase):
         self.assertEqual(d['embedded_field'], [{'string': 'Hi'}])
 
     def test_instance_is_set_on_setattr(self):
-
         class Email(EmbeddedDocument):
             email = EmailField()
 
@@ -698,6 +672,7 @@ class InstanceTest(unittest.TestCase):
             email = EmbeddedDocumentField(Email)
 
         Account.drop_collection()
+
         acc = Account()
         acc.email = Email(email='test@example.com')
         self.assertHasInstance(acc._data["email"], acc)
@@ -707,7 +682,6 @@ class InstanceTest(unittest.TestCase):
         self.assertHasInstance(acc1._data["email"], acc1)
 
     def test_instance_is_set_on_setattr_on_embedded_document_list(self):
-
         class Email(EmbeddedDocument):
             email = EmailField()
 
@@ -853,32 +827,28 @@ class InstanceTest(unittest.TestCase):
         self.assertDbEqual([dict(other_doc.to_mongo()), dict(doc.to_mongo())])
 
     def test_save(self):
-        """Ensure that a document may be saved in the database.
+        """Ensure that a document may be saved in the database."""
-        """
+
         # Create person object and save it to the database
         person = self.Person(name='Test User', age=30)
         person.save()
+
         # Ensure that the object is in the database
         collection = self.db[self.Person._get_collection_name()]
         person_obj = collection.find_one({'name': 'Test User'})
         self.assertEqual(person_obj['name'], 'Test User')
         self.assertEqual(person_obj['age'], 30)
         self.assertEqual(person_obj['_id'], person.id)
-        # Test skipping validation on save
 
+        # Test skipping validation on save
         class Recipient(Document):
             email = EmailField(required=True)
 
         recipient = Recipient(email='root@localhost')
         self.assertRaises(ValidationError, recipient.save)
-
+        recipient.save(validate=False)
-        try:
-            recipient.save(validate=False)
-        except ValidationError:
-            self.fail()
 
     def test_save_to_a_value_that_equates_to_false(self):
-
         class Thing(EmbeddedDocument):
             count = IntField()
 
@@ -898,7 +868,6 @@ class InstanceTest(unittest.TestCase):
         self.assertEqual(user.thing.count, 0)
 
     def test_save_max_recursion_not_hit(self):
-
         class Person(Document):
             name = StringField()
             parent = ReferenceField('self')
@@ -924,7 +893,6 @@ class InstanceTest(unittest.TestCase):
         p0.save()
 
     def test_save_max_recursion_not_hit_with_file_field(self):
-
         class Foo(Document):
             name = StringField()
             picture = FileField()
@@ -948,7 +916,6 @@ class InstanceTest(unittest.TestCase):
             self.assertEqual(b.picture, b.bar.picture, b.bar.bar.picture)
 
     def test_save_cascades(self):
-
         class Person(Document):
             name = StringField()
             parent = ReferenceField('self')
@@ -971,7 +938,6 @@ class InstanceTest(unittest.TestCase):
         self.assertEqual(p1.name, p.parent.name)
 
     def test_save_cascade_kwargs(self):
-
         class Person(Document):
             name = StringField()
             parent = ReferenceField('self')
@@ -992,7 +958,6 @@ class InstanceTest(unittest.TestCase):
         self.assertEqual(p1.name, p2.parent.name)
 
     def test_save_cascade_meta_false(self):
-
         class Person(Document):
             name = StringField()
             parent = ReferenceField('self')
@@ -1021,7 +986,6 @@ class InstanceTest(unittest.TestCase):
         self.assertEqual(p1.name, p.parent.name)
 
     def test_save_cascade_meta_true(self):
-
         class Person(Document):
             name = StringField()
             parent = ReferenceField('self')
@@ -1046,7 +1010,6 @@ class InstanceTest(unittest.TestCase):
         self.assertNotEqual(p1.name, p.parent.name)
 
     def test_save_cascades_generically(self):
-
         class Person(Document):
             name = StringField()
             parent = GenericReferenceField()
@@ -1072,7 +1035,6 @@ class InstanceTest(unittest.TestCase):
         self.assertEqual(p1.name, p.parent.name)
 
     def test_save_atomicity_condition(self):
-
         class Widget(Document):
             toggle = BooleanField(default=False)
             count = IntField(default=0)
@@ -1150,7 +1112,8 @@ class InstanceTest(unittest.TestCase):
 
     def test_update(self):
         """Ensure that an existing document is updated instead of be
-        overwritten."""
+        overwritten.
+        """
         # Create person object and save it to the database
         person = self.Person(name='Test User', age=30)
         person.save()
@@ -1254,7 +1217,6 @@ class InstanceTest(unittest.TestCase):
         self.assertEqual(2, self.Person.objects.count())
 
     def test_can_save_if_not_included(self):
-
         class EmbeddedDoc(EmbeddedDocument):
             pass
 
@@ -1341,10 +1303,7 @@ class InstanceTest(unittest.TestCase):
             doc2.update(set__name=doc1.name)
 
     def test_embedded_update(self):
-        """
+        """Test update on `EmbeddedDocumentField` fields."""
-        Test update on `EmbeddedDocumentField` fields
-        """
-
         class Page(EmbeddedDocument):
             log_message = StringField(verbose_name="Log message",
                                       required=True)
@@ -1365,11 +1324,9 @@ class InstanceTest(unittest.TestCase):
         self.assertEqual(site.page.log_message, "Error: Dummy message")
 
     def test_embedded_update_db_field(self):
+        """Test update on `EmbeddedDocumentField` fields when db_field
+        is other than default.
         """
-        Test update on `EmbeddedDocumentField` fields when db_field is other
-        than default.
-        """
-
         class Page(EmbeddedDocument):
             log_message = StringField(verbose_name="Log message",
                                       db_field="page_log_message",
@@ -1392,9 +1349,7 @@ class InstanceTest(unittest.TestCase):
         self.assertEqual(site.page.log_message, "Error: Dummy message")
 
     def test_save_only_changed_fields(self):
-        """Ensure save only sets / unsets changed fields
+        """Ensure save only sets / unsets changed fields."""
-        """
-
         class User(self.Person):
             active = BooleanField(default=True)
 
@@ -1514,8 +1469,8 @@ class InstanceTest(unittest.TestCase):
             self.assertEqual(q, 3)
 
     def test_set_unset_one_operation(self):
-        """Ensure that $set and $unset actions are performed in the same
+        """Ensure that $set and $unset actions are performed in the
-        operation.
+        same operation.
         """
         class FooBar(Document):
             foo = StringField(default=None)
@@ -1536,9 +1491,7 @@ class InstanceTest(unittest.TestCase):
             self.assertEqual(1, q)
 
     def test_save_only_changed_fields_recursive(self):
-        """Ensure save only sets / unsets changed fields
+        """Ensure save only sets / unsets changed fields."""
-        """
-
         class Comment(EmbeddedDocument):
             published = BooleanField(default=True)
 
@@ -1578,8 +1531,7 @@ class InstanceTest(unittest.TestCase):
         self.assertFalse(person.comments_dict['first_post'].published)
 
     def test_delete(self):
-        """Ensure that document may be deleted using the delete method.
+        """Ensure that document may be deleted using the delete method."""
-        """
         person = self.Person(name="Test User", age=30)
         person.save()
         self.assertEqual(self.Person.objects.count(), 1)
@@ -1587,33 +1539,34 @@ class InstanceTest(unittest.TestCase):
         self.assertEqual(self.Person.objects.count(), 0)
 
     def test_save_custom_id(self):
-        """Ensure that a document may be saved with a custom _id.
+        """Ensure that a document may be saved with a custom _id."""
-        """
+
         # Create person object and save it to the database
         person = self.Person(name='Test User', age=30,
                              id='497ce96f395f2f052a494fd4')
         person.save()
+
         # Ensure that the object is in the database with the correct _id
         collection = self.db[self.Person._get_collection_name()]
         person_obj = collection.find_one({'name': 'Test User'})
         self.assertEqual(str(person_obj['_id']), '497ce96f395f2f052a494fd4')
 
     def test_save_custom_pk(self):
-        """
+        """Ensure that a document may be saved with a custom _id using
-        Ensure that a document may be saved with a custom _id using pk alias.
+        pk alias.
         """
         # Create person object and save it to the database
         person = self.Person(name='Test User', age=30,
                              pk='497ce96f395f2f052a494fd4')
         person.save()
+
         # Ensure that the object is in the database with the correct _id
         collection = self.db[self.Person._get_collection_name()]
         person_obj = collection.find_one({'name': 'Test User'})
         self.assertEqual(str(person_obj['_id']), '497ce96f395f2f052a494fd4')
 
     def test_save_list(self):
-        """Ensure that a list field may be properly saved.
+        """Ensure that a list field may be properly saved."""
-        """
         class Comment(EmbeddedDocument):
             content = StringField()
 
@@ -1636,8 +1589,6 @@ class InstanceTest(unittest.TestCase):
         for comment_obj, comment in zip(post_obj['comments'], comments):
             self.assertEqual(comment_obj['content'], comment['content'])
 
-        BlogPost.drop_collection()
-
     def test_list_search_by_embedded(self):
         class User(Document):
             username = StringField(required=True)
@@ -1697,8 +1648,8 @@ class InstanceTest(unittest.TestCase):
             list(Page.objects.filter(comments__user=u3)))
 
     def test_save_embedded_document(self):
-        """Ensure that a document with an embedded document field may be
+        """Ensure that a document with an embedded document field may
-        saved in the database.
+        be saved in the database.
         """
         class EmployeeDetails(EmbeddedDocument):
             position = StringField()
@@ -1717,13 +1668,13 @@ class InstanceTest(unittest.TestCase):
         employee_obj = collection.find_one({'name': 'Test Employee'})
         self.assertEqual(employee_obj['name'], 'Test Employee')
         self.assertEqual(employee_obj['age'], 50)
+
         # Ensure that the 'details' embedded object saved correctly
         self.assertEqual(employee_obj['details']['position'], 'Developer')
 
     def test_embedded_update_after_save(self):
-        """
+        """Test update of `EmbeddedDocumentField` attached to a newly
-        Test update of `EmbeddedDocumentField` attached to a newly saved
+        saved document.
-        document.
         """
         class Page(EmbeddedDocument):
             log_message = StringField(verbose_name="Log message",
@@ -1744,8 +1695,8 @@ class InstanceTest(unittest.TestCase):
         self.assertEqual(site.page.log_message, "Error: Dummy message")
 
     def test_updating_an_embedded_document(self):
-        """Ensure that a document with an embedded document field may be
+        """Ensure that a document with an embedded document field may
-        saved in the database.
+        be saved in the database.
         """
         class EmployeeDetails(EmbeddedDocument):
             position = StringField()
@@ -1780,7 +1731,6 @@ class InstanceTest(unittest.TestCase):
         self.assertEqual(promoted_employee.details, None)
 
     def test_object_mixins(self):
-
         class NameMixin(object):
             name = StringField()
 
@@ -1819,9 +1769,9 @@ class InstanceTest(unittest.TestCase):
         self.assertEqual(t.count, 12)
 
     def test_save_reference(self):
-        """Ensure that a document reference field may be saved in the database.
+        """Ensure that a document reference field may be saved in the
+        database.
         """
-
         class BlogPost(Document):
             meta = {'collection': 'blogpost_1'}
             content = StringField()
@@ -1852,8 +1802,6 @@ class InstanceTest(unittest.TestCase):
         author = list(self.Person.objects(name='Test User'))[-1]
         self.assertEqual(author.age, 25)
 
-        BlogPost.drop_collection()
-
     def test_duplicate_db_fields_raise_invalid_document_error(self):
         """Ensure a InvalidDocumentError is thrown if duplicate fields
         declare the same db_field.
@@ -1864,7 +1812,7 @@ class InstanceTest(unittest.TestCase):
                 name2 = StringField(db_field='name')
 
     def test_invalid_son(self):
-        """Raise an error if loading invalid data"""
+        """Raise an error if loading invalid data."""
         class Occurrence(EmbeddedDocument):
             number = IntField()
 
@@ -1887,9 +1835,9 @@ class InstanceTest(unittest.TestCase):
             Word._from_son('this is not a valid SON dict')
 
     def test_reverse_delete_rule_cascade_and_nullify(self):
-        """Ensure that a referenced document is also deleted upon deletion.
+        """Ensure that a referenced document is also deleted upon
+        deletion.
         """
-
         class BlogPost(Document):
             content = StringField()
             author = ReferenceField(self.Person, reverse_delete_rule=CASCADE)
@@ -1944,7 +1892,8 @@ class InstanceTest(unittest.TestCase):
         self.assertEqual(Book.objects.count(), 0)
 
     def test_reverse_delete_rule_with_shared_id_among_collections(self):
-        """Ensure that cascade delete rule doesn't mix id among collections.
+        """Ensure that cascade delete rule doesn't mix id among
+        collections.
         """
         class User(Document):
             id = IntField(primary_key=True)
@@ -1975,10 +1924,9 @@ class InstanceTest(unittest.TestCase):
         self.assertEqual(Book.objects.get(), book_2)
 
     def test_reverse_delete_rule_with_document_inheritance(self):
-        """Ensure that a referenced document is also deleted upon deletion
+        """Ensure that a referenced document is also deleted upon
-        of a child document.
+        deletion of a child document.
         """
-
         class Writer(self.Person):
             pass
 
@@ -2010,10 +1958,9 @@ class InstanceTest(unittest.TestCase):
         self.assertEqual(BlogPost.objects.count(), 0)
 
     def test_reverse_delete_rule_cascade_and_nullify_complex_field(self):
-        """Ensure that a referenced document is also deleted upon deletion for
+        """Ensure that a referenced document is also deleted upon
-        complex fields.
+        deletion for complex fields.
         """
-
         class BlogPost(Document):
             content = StringField()
             authors = ListField(ReferenceField(
@@ -2022,7 +1969,6 @@ class InstanceTest(unittest.TestCase):
                 self.Person, reverse_delete_rule=NULLIFY))
 
         self.Person.drop_collection()
-
         BlogPost.drop_collection()
 
         author = self.Person(name='Test User')
@@ -2046,10 +1992,10 @@ class InstanceTest(unittest.TestCase):
         self.assertEqual(BlogPost.objects.count(), 0)
 
     def test_reverse_delete_rule_cascade_triggers_pre_delete_signal(self):
-        """ ensure the pre_delete signal is triggered upon a cascading deletion
+        """Ensure the pre_delete signal is triggered upon a cascading
-        setup a blog post with content, an author and editor
+        deletion setup a blog post with content, an author and editor
-        delete the author which triggers deletion of blogpost via cascade
+        delete the author which triggers deletion of blogpost via
-        blog post's pre_delete signal alters an editor attribute
+        cascade blog post's pre_delete signal alters an editor attribute.
         """
         class Editor(self.Person):
             review_queue = IntField(default=0)
@@ -2077,6 +2023,7 @@ class InstanceTest(unittest.TestCase):
 
         # delete the author, the post is also deleted due to the CASCADE rule
         author.delete()
+
         # the pre-delete signal should have decremented the editor's queue
         editor = Editor.objects(name='Max P.').get()
         self.assertEqual(editor.review_queue, 0)
@@ -2085,7 +2032,6 @@ class InstanceTest(unittest.TestCase):
         """Ensure that Bi-Directional relationships work with
         reverse_delete_rule
         """
-
         class Bar(Document):
             content = StringField()
             foo = ReferenceField('Foo')
@@ -2131,8 +2077,8 @@ class InstanceTest(unittest.TestCase):
                 mother = ReferenceField('Person', reverse_delete_rule=DENY)
 
     def test_reverse_delete_rule_cascade_recurs(self):
-        """Ensure that a chain of documents is also deleted upon cascaded
+        """Ensure that a chain of documents is also deleted upon
-        deletion.
+        cascaded deletion.
         """
         class BlogPost(Document):
             content = StringField()
@@ -2162,15 +2108,10 @@ class InstanceTest(unittest.TestCase):
         author.delete()
         self.assertEqual(Comment.objects.count(), 0)
 
-        self.Person.drop_collection()
-        BlogPost.drop_collection()
-        Comment.drop_collection()
-
     def test_reverse_delete_rule_deny(self):
-        """Ensure that a document cannot be referenced if there are still
+        """Ensure that a document cannot be referenced if there are
-        documents referring to it.
+        still documents referring to it.
         """
-
         class BlogPost(Document):
             content = StringField()
             author = ReferenceField(self.Person, reverse_delete_rule=DENY)
@@ -2198,11 +2139,7 @@ class InstanceTest(unittest.TestCase):
         author.delete()
         self.assertEqual(self.Person.objects.count(), 1)
 
-        self.Person.drop_collection()
-        BlogPost.drop_collection()
-
     def subclasses_and_unique_keys_works(self):
-
         class A(Document):
             pass
 
@@ -2218,12 +2155,9 @@ class InstanceTest(unittest.TestCase):
 
         self.assertEqual(A.objects.count(), 2)
         self.assertEqual(B.objects.count(), 1)
-        A.drop_collection()
-        B.drop_collection()
 
     def test_document_hash(self):
-        """Test document in list, dict, set
+        """Test document in list, dict, set."""
-        """
         class User(Document):
             pass
 
@@ -2266,11 +2200,9 @@ class InstanceTest(unittest.TestCase):
 
         # in Set
         all_user_set = set(User.objects.all())
-
         self.assertTrue(u1 in all_user_set)
 
     def test_picklable(self):
-
         pickle_doc = PickleTest(number=1, string="One", lists=['1', '2'])
         pickle_doc.embedded = PickleEmbedded()
         pickled_doc = pickle.dumps(pickle_doc)  # make sure pickling works even before the doc is saved
@@ -2296,7 +2228,6 @@ class InstanceTest(unittest.TestCase):
         self.assertEqual(pickle_doc.lists, ["1", "2", "3"])
 
     def test_regular_document_pickle(self):
-
         pickle_doc = PickleTest(number=1, string="One", lists=['1', '2'])
         pickled_doc = pickle.dumps(pickle_doc)  # make sure pickling works even before the doc is saved
         pickle_doc.save()
@@ -2319,7 +2250,6 @@ class InstanceTest(unittest.TestCase):
         fixtures.PickleTest = PickleTest
 
     def test_dynamic_document_pickle(self):
-
         pickle_doc = PickleDynamicTest(
             name="test", number=1, string="One", lists=['1', '2'])
         pickle_doc.embedded = PickleDynamicEmbedded(foo="Bar")
@@ -2358,7 +2288,6 @@ class InstanceTest(unittest.TestCase):
                 validate = DictField()
 
     def test_mutating_documents(self):
-
         class B(EmbeddedDocument):
             field1 = StringField(default='field1')
 
@@ -2366,6 +2295,7 @@ class InstanceTest(unittest.TestCase):
             b = EmbeddedDocumentField(B, default=lambda: B())
 
         A.drop_collection()
+
         a = A()
         a.save()
         a.reload()
@@ -2389,12 +2319,13 @@ class InstanceTest(unittest.TestCase):
         self.assertEqual(a.b.field2.c_field, 'new value')
 
     def test_can_save_false_values(self):
-        """Ensures you can save False values on save"""
+        """Ensures you can save False values on save."""
         class Doc(Document):
             foo = StringField()
             archived = BooleanField(default=False, required=True)
 
         Doc.drop_collection()
+
         d = Doc()
         d.save()
         d.archived = False
@@ -2403,11 +2334,12 @@ class InstanceTest(unittest.TestCase):
         self.assertEqual(Doc.objects(archived=False).count(), 1)
 
     def test_can_save_false_values_dynamic(self):
-        """Ensures you can save False values on dynamic docs"""
+        """Ensures you can save False values on dynamic docs."""
         class Doc(DynamicDocument):
             foo = StringField()
 
         Doc.drop_collection()
+
         d = Doc()
         d.save()
         d.archived = False
@@ -2447,7 +2379,7 @@ class InstanceTest(unittest.TestCase):
             Collection.update = orig_update
 
     def test_db_alias_tests(self):
-        """ DB Alias tests """
+        """DB Alias tests."""
         # mongoenginetest - Is default connection alias from setUp()
         # Register Aliases
         register_connection('testdb-1', 'mongoenginetest2')
@@ -2509,8 +2441,7 @@ class InstanceTest(unittest.TestCase):
             get_db("testdb-3")[AuthorBooks._get_collection_name()])
 
     def test_db_alias_overrides(self):
-        """db_alias can be overriden
+        """Test db_alias can be overriden."""
-        """
         # Register a connection with db_alias testdb-2
         register_connection('testdb-2', 'mongoenginetest2')
 
@@ -2534,8 +2465,7 @@ class InstanceTest(unittest.TestCase):
                          B._get_collection().database.name)
 
     def test_db_alias_propagates(self):
-        """db_alias propagates?
+        """db_alias propagates?"""
-        """
         register_connection('testdb-1', 'mongoenginetest2')
 
         class A(Document):
@@ -2548,8 +2478,7 @@ class InstanceTest(unittest.TestCase):
         self.assertEqual('testdb-1', B._meta.get('db_alias'))
 
     def test_db_ref_usage(self):
-        """ DB Ref usage  in dict_fields"""
+        """DB Ref usage in dict_fields."""
-
         class User(Document):
             name = StringField()
 
@@ -2784,7 +2713,6 @@ class InstanceTest(unittest.TestCase):
         self.assertEqual(user.thing._data['data'], [1, 2, 3])
 
     def test_spaces_in_keys(self):
-
         class Embedded(DynamicEmbeddedDocument):
             pass
 
@@ -2873,7 +2801,6 @@ class InstanceTest(unittest.TestCase):
             log.machine = "127.0.0.1"
 
     def test_kwargs_simple(self):
-
         class Embedded(EmbeddedDocument):
             name = StringField()
 
@@ -2893,7 +2820,6 @@ class InstanceTest(unittest.TestCase):
         self.assertEqual(classic_doc._data, dict_doc._data)
 
     def test_kwargs_complex(self):
-
         class Embedded(EmbeddedDocument):
             name = StringField()
 
@@ -2916,36 +2842,35 @@ class InstanceTest(unittest.TestCase):
         self.assertEqual(classic_doc._data, dict_doc._data)
 
     def test_positional_creation(self):
-        """Ensure that document may be created using positional arguments.
+        """Ensure that document may be created using positional arguments."""
-        """
         person = self.Person("Test User", 42)
         self.assertEqual(person.name, "Test User")
         self.assertEqual(person.age, 42)
 
     def test_mixed_creation(self):
-        """Ensure that document may be created using mixed arguments.
+        """Ensure that document may be created using mixed arguments."""
-        """
         person = self.Person("Test User", age=42)
         self.assertEqual(person.name, "Test User")
         self.assertEqual(person.age, 42)
 
     def test_positional_creation_embedded(self):
-        """Ensure that embedded document may be created using positional arguments.
+        """Ensure that embedded document may be created using positional
+        arguments.
         """
         job = self.Job("Test Job", 4)
         self.assertEqual(job.name, "Test Job")
         self.assertEqual(job.years, 4)
 
     def test_mixed_creation_embedded(self):
-        """Ensure that embedded document may be created using mixed arguments.
+        """Ensure that embedded document may be created using mixed
+        arguments.
         """
         job = self.Job("Test Job", years=4)
         self.assertEqual(job.name, "Test Job")
         self.assertEqual(job.years, 4)
 
     def test_mixed_creation_dynamic(self):
-        """Ensure that document may be created using mixed arguments.
+        """Ensure that document may be created using mixed arguments."""
-        """
         class Person(DynamicDocument):
             name = StringField()
 
@@ -2954,14 +2879,14 @@ class InstanceTest(unittest.TestCase):
         self.assertEqual(person.age, 42)
 
     def test_bad_mixed_creation(self):
-        """Ensure that document gives correct error when duplicating arguments
+        """Ensure that document gives correct error when duplicating
+        arguments.
         """
         with self.assertRaises(TypeError):
             return self.Person("Test User", 42, name="Bad User")
 
     def test_data_contains_id_field(self):
-        """Ensure that asking for _data returns 'id'
+        """Ensure that asking for _data returns 'id'."""
-        """
         class Person(Document):
             name = StringField()
 
@@ -2973,7 +2898,6 @@ class InstanceTest(unittest.TestCase):
         self.assertEqual(person._data.get('id'), person.id)
 
     def test_complex_nesting_document_and_embedded_document(self):
-
         class Macro(EmbeddedDocument):
             value = DynamicField(default="UNDEFINED")
 
@@ -3016,7 +2940,6 @@ class InstanceTest(unittest.TestCase):
             system.nodes["node"].parameters["param"].macros["test"].value)
 
     def test_embedded_document_equality(self):
-
         class Test(Document):
             field = StringField(required=True)
 
@@ -3202,8 +3125,7 @@ class InstanceTest(unittest.TestCase):
         self.assertEqual(idx, 2)
 
     def test_falsey_pk(self):
-        """Ensure that we can create and update a document with Falsey PK.
+        """Ensure that we can create and update a document with Falsey PK."""
-        """
         class Person(Document):
             age = IntField(primary_key=True)
             height = FloatField()