diff --git a/tests/document/test_dynamic.py b/tests/document/test_dynamic.py
index a6f46862..0032dfd9 100644
--- a/tests/document/test_dynamic.py
+++ b/tests/document/test_dynamic.py
@@ -1,8 +1,9 @@
 import unittest
 
+import pytest
+
 from mongoengine import *
 from tests.utils import MongoDBTestCase
-import pytest
 
 __all__ = ("TestDynamicDocument",)
 
diff --git a/tests/document/test_indexes.py b/tests/document/test_indexes.py
index 6c31054a..dc6c5c8e 100644
--- a/tests/document/test_indexes.py
+++ b/tests/document/test_indexes.py
@@ -5,11 +5,11 @@ from datetime import datetime
 from nose.plugins.skip import SkipTest
 from pymongo.collation import Collation
 from pymongo.errors import OperationFailure
+import pytest
 from six import iteritems
 
 from mongoengine import *
 from mongoengine.connection import get_db
-import pytest
 
 
 class TestIndexes(unittest.TestCase):
diff --git a/tests/document/test_inheritance.py b/tests/document/test_inheritance.py
index b6b6088a..5072f841 100644
--- a/tests/document/test_inheritance.py
+++ b/tests/document/test_inheritance.py
@@ -2,6 +2,7 @@
 import unittest
 import warnings
 
+import pytest
 from six import iteritems
 
 from mongoengine import (
@@ -17,7 +18,6 @@ from mongoengine import (
 from mongoengine.pymongo_support import list_collection_names
 from tests.fixtures import Base
 from tests.utils import MongoDBTestCase
-import pytest
 
 
 class TestInheritance(MongoDBTestCase):
@@ -335,9 +335,7 @@ class TestInheritance(MongoDBTestCase):
             name = StringField()
 
         # can't inherit because Animal didn't explicitly allow inheritance
-        with pytest.raises(
-            ValueError, match="Document Animal may not be subclassed"
-        ) as exc_info:
+        with pytest.raises(ValueError, match="Document Animal may not be subclassed"):
 
             class Dog(Animal):
                 pass
@@ -475,7 +473,7 @@ class TestInheritance(MongoDBTestCase):
             meta = {"abstract": True, "allow_inheritance": False}
 
         city = City(continent="asia")
-        assert None == city.pk
+        assert city.pk is None
         # TODO: expected error? Shouldn't we create a new error type?
         with pytest.raises(KeyError):
             setattr(city, "pk", 1)
diff --git a/tests/document/test_instance.py b/tests/document/test_instance.py
index 57815355..9d533129 100644
--- a/tests/document/test_instance.py
+++ b/tests/document/test_instance.py
@@ -9,6 +9,7 @@ from datetime import datetime
 import bson
 from bson import DBRef, ObjectId
 from pymongo.errors import DuplicateKeyError
+import pytest
 from six import iteritems
 
 from mongoengine import *
@@ -36,7 +37,6 @@ from tests.fixtures import (
     PickleTest,
 )
 from tests.utils import MongoDBTestCase, get_as_pymongo
-import pytest
 
 TEST_IMAGE_PATH = os.path.join(os.path.dirname(__file__), "../fields/mongoengine.png")
 
@@ -96,7 +96,7 @@ class TestInstance(MongoDBTestCase):
         assert Log.objects.count() == 10
 
         options = Log.objects._collection.options()
-        assert options["capped"] == True
+        assert options["capped"] is True
         assert options["max"] == 10
         assert options["size"] == 4096
 
@@ -122,7 +122,7 @@ class TestInstance(MongoDBTestCase):
         Log().save()
 
         options = Log.objects._collection.options()
-        assert options["capped"] == True
+        assert options["capped"] is True
         assert options["max"] == 10
         assert options["size"] == 10 * 2 ** 20
 
@@ -150,7 +150,7 @@ class TestInstance(MongoDBTestCase):
         Log().save()
 
         options = Log.objects._collection.options()
-        assert options["capped"] == True
+        assert options["capped"] is True
         assert options["size"] >= 10000
 
         # Check that the document with odd max_size value can be recreated
@@ -350,7 +350,7 @@ class TestInstance(MongoDBTestCase):
             name = StringField()
             meta = {"allow_inheritance": True}
 
-        with pytest.raises(ValueError, match="Cannot override primary key field") as e:
+        with pytest.raises(ValueError, match="Cannot override primary key field"):
 
             class EmailUser(User):
                 email = StringField(primary_key=True)
@@ -620,7 +620,7 @@ class TestInstance(MongoDBTestCase):
             f.reload()
 
     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 is False."""
 
         class Post(Document):
             meta = {"strict": False}
@@ -832,13 +832,13 @@ class TestInstance(MongoDBTestCase):
         t = TestDocument(status="published")
         t.save(clean=False)
         assert t.status == "published"
-        assert t.cleaned == False
+        assert t.cleaned is False
 
         t = TestDocument(status="published")
-        assert t.cleaned == False
+        assert t.cleaned is False
         t.save(clean=True)
         assert t.status == "published"
-        assert t.cleaned == True
+        assert t.cleaned is True
         raw_doc = get_as_pymongo(t)
         # Make sure clean changes makes it to the db
         assert raw_doc == {"status": "published", "cleaned": True, "_id": t.id}
@@ -1600,7 +1600,7 @@ class TestInstance(MongoDBTestCase):
         person = self.Person.objects.get()
         assert person.name == "User"
         assert person.age == 21
-        assert person.active == False
+        assert person.active is False
 
     def test__get_changed_fields_same_ids_reference_field_does_not_enters_infinite_loop_embedded_doc(
         self,
@@ -2521,9 +2521,9 @@ class TestInstance(MongoDBTestCase):
         assert all_user_dic.get(u1, False) == "OK"
         assert all_user_dic.get(u2, False) == "OK"
         assert all_user_dic.get(u3, False) == "OK"
-        assert all_user_dic.get(u4, False) == False  # New object
-        assert all_user_dic.get(b1, False) == False  # Other object
-        assert all_user_dic.get(b2, False) == False  # Other object
+        assert all_user_dic.get(u4, False) is False  # New object
+        assert all_user_dic.get(b1, False) is False  # Other object
+        assert all_user_dic.get(b2, False) is False  # Other object
 
         # Make sure docs are properly identified in a set (__hash__ is used
         # for hashing the docs).
@@ -3216,7 +3216,7 @@ class TestInstance(MongoDBTestCase):
     def test_mixed_creation(self):
         """Document cannot be instantiated using mixed arguments."""
         with pytest.raises(TypeError) as exc_info:
-            person = self.Person("Test User", age=42)
+            self.Person("Test User", age=42)
 
         expected_msg = (
             "Instantiating a document with positional arguments is not "
@@ -3227,7 +3227,7 @@ class TestInstance(MongoDBTestCase):
     def test_positional_creation_embedded(self):
         """Embedded document cannot be created using positional arguments."""
         with pytest.raises(TypeError) as exc_info:
-            job = self.Job("Test Job", 4)
+            self.Job("Test Job", 4)
 
         expected_msg = (
             "Instantiating a document with positional arguments is not "
@@ -3238,7 +3238,7 @@ class TestInstance(MongoDBTestCase):
     def test_mixed_creation_embedded(self):
         """Embedded document cannot be created using mixed arguments."""
         with pytest.raises(TypeError) as exc_info:
-            job = self.Job("Test Job", years=4)
+            self.Job("Test Job", years=4)
 
         expected_msg = (
             "Instantiating a document with positional arguments is not "
@@ -3432,7 +3432,7 @@ class TestInstance(MongoDBTestCase):
             meta = {"shard_key": ("id", "name")}
 
         p = Person.from_json('{"name": "name", "age": 27}', created=True)
-        assert p._created == True
+        assert p._created is True
         p.name = "new name"
         p.id = "12345"
         assert p.name == "new name"
@@ -3450,7 +3450,7 @@ class TestInstance(MongoDBTestCase):
             meta = {"shard_key": ("id", "name")}
 
         p = Person._from_son({"name": "name", "age": 27}, created=True)
-        assert p._created == True
+        assert p._created is True
         p.name = "new name"
         p.id = "12345"
         assert p.name == "new name"
@@ -3463,7 +3463,7 @@ class TestInstance(MongoDBTestCase):
         Person.objects.delete()
 
         p = Person.from_json('{"name": "name"}', created=False)
-        assert p._created == False
+        assert p._created is False
         assert p.id is None
 
         # Make sure the document is subsequently persisted correctly.
@@ -3483,7 +3483,7 @@ class TestInstance(MongoDBTestCase):
         p = Person.from_json(
             '{"_id": "5b85a8b04ec5dc2da388296e", "name": "name"}', created=False
         )
-        assert p._created == False
+        assert p._created is False
         assert p._changed_fields == []
         assert p.name == "name"
         assert p.id == ObjectId("5b85a8b04ec5dc2da388296e")
diff --git a/tests/document/test_validation.py b/tests/document/test_validation.py
index dfae5bae..2439f283 100644
--- a/tests/document/test_validation.py
+++ b/tests/document/test_validation.py
@@ -2,9 +2,10 @@
 import unittest
 from datetime import datetime
 
+import pytest
+
 from mongoengine import *
 from tests.utils import MongoDBTestCase
-import pytest
 
 
 class TestValidatorError(MongoDBTestCase):
diff --git a/tests/fields/test_binary_field.py b/tests/fields/test_binary_field.py
index 86ee2654..e2a1b8d6 100644
--- a/tests/fields/test_binary_field.py
+++ b/tests/fields/test_binary_field.py
@@ -2,12 +2,11 @@
 import uuid
 
 from bson import Binary
-from nose.plugins.skip import SkipTest
+import pytest
 import six
 
 from mongoengine import *
 from tests.utils import MongoDBTestCase
-import pytest
 
 BIN_VALUE = six.b(
     "\xa9\xf3\x8d(\xd7\x03\x84\xb4k[\x0f\xe3\xa2\x19\x85p[J\xa3\xd2>\xde\xe6\x87\xb1\x7f\xc6\xe6\xd9r\x18\xf5"
diff --git a/tests/fields/test_boolean_field.py b/tests/fields/test_boolean_field.py
index b38b5ea4..041f9f56 100644
--- a/tests/fields/test_boolean_field.py
+++ b/tests/fields/test_boolean_field.py
@@ -1,9 +1,9 @@
 # -*- coding: utf-8 -*-
-from mongoengine import *
-
-from tests.utils import MongoDBTestCase, get_as_pymongo
 import pytest
 
+from mongoengine import *
+from tests.utils import MongoDBTestCase, get_as_pymongo
+
 
 class TestBooleanField(MongoDBTestCase):
     def test_storage(self):
diff --git a/tests/fields/test_cached_reference_field.py b/tests/fields/test_cached_reference_field.py
index e404aae0..bb4c57d2 100644
--- a/tests/fields/test_cached_reference_field.py
+++ b/tests/fields/test_cached_reference_field.py
@@ -1,11 +1,11 @@
 # -*- coding: utf-8 -*-
 from decimal import Decimal
 
-from mongoengine import *
-
-from tests.utils import MongoDBTestCase
 import pytest
 
+from mongoengine import *
+from tests.utils import MongoDBTestCase
+
 
 class TestCachedReferenceField(MongoDBTestCase):
     def test_get_and_save(self):
diff --git a/tests/fields/test_date_field.py b/tests/fields/test_date_field.py
index 46fa4f0f..e94ed0ce 100644
--- a/tests/fields/test_date_field.py
+++ b/tests/fields/test_date_field.py
@@ -1,5 +1,7 @@
 # -*- coding: utf-8 -*-
 import datetime
+
+import pytest
 import six
 
 try:
@@ -8,9 +10,7 @@ except ImportError:
     dateutil = None
 
 from mongoengine import *
-
 from tests.utils import MongoDBTestCase
-import pytest
 
 
 class TestDateField(MongoDBTestCase):
diff --git a/tests/fields/test_datetime_field.py b/tests/fields/test_datetime_field.py
index 8db491c6..70debac5 100644
--- a/tests/fields/test_datetime_field.py
+++ b/tests/fields/test_datetime_field.py
@@ -1,5 +1,7 @@
 # -*- coding: utf-8 -*-
 import datetime as dt
+
+import pytest
 import six
 
 try:
@@ -11,7 +13,6 @@ from mongoengine import *
 from mongoengine import connection
 
 from tests.utils import MongoDBTestCase
-import pytest
 
 
 class TestDateTimeField(MongoDBTestCase):
diff --git a/tests/fields/test_decimal_field.py b/tests/fields/test_decimal_field.py
index b5b95363..c531166f 100644
--- a/tests/fields/test_decimal_field.py
+++ b/tests/fields/test_decimal_field.py
@@ -1,11 +1,11 @@
 # -*- coding: utf-8 -*-
 from decimal import Decimal
 
-from mongoengine import *
-
-from tests.utils import MongoDBTestCase
 import pytest
 
+from mongoengine import *
+from tests.utils import MongoDBTestCase
+
 
 class TestDecimalField(MongoDBTestCase):
     def test_validation(self):
diff --git a/tests/fields/test_dict_field.py b/tests/fields/test_dict_field.py
index 7dda2a9c..e88128f9 100644
--- a/tests/fields/test_dict_field.py
+++ b/tests/fields/test_dict_field.py
@@ -1,9 +1,10 @@
 # -*- coding: utf-8 -*-
+import pytest
+
 from mongoengine import *
 from mongoengine.base import BaseDict
 
 from tests.utils import MongoDBTestCase, get_as_pymongo
-import pytest
 
 
 class TestDictField(MongoDBTestCase):
@@ -290,7 +291,7 @@ class TestDictField(MongoDBTestCase):
         e.save()
         e.update(set__mapping={"ints": [3, 4]})
         e.reload()
-        assert BaseDict == type(e.mapping)
+        assert isinstance(e.mapping, BaseDict)
         assert {"ints": [3, 4]} == e.mapping
 
         # try creating an invalid mapping
diff --git a/tests/fields/test_email_field.py b/tests/fields/test_email_field.py
index 902a7c42..55255df5 100644
--- a/tests/fields/test_email_field.py
+++ b/tests/fields/test_email_field.py
@@ -2,11 +2,11 @@
 import sys
 from unittest import SkipTest
 
-from mongoengine import *
-
-from tests.utils import MongoDBTestCase
 import pytest
 
+from mongoengine import *
+from tests.utils import MongoDBTestCase
+
 
 class TestEmailField(MongoDBTestCase):
     def test_generic_behavior(self):
diff --git a/tests/fields/test_embedded_document_field.py b/tests/fields/test_embedded_document_field.py
index 9e6871cc..eeddac1e 100644
--- a/tests/fields/test_embedded_document_field.py
+++ b/tests/fields/test_embedded_document_field.py
@@ -1,4 +1,6 @@
 # -*- coding: utf-8 -*-
+import pytest
+
 from mongoengine import (
     Document,
     EmbeddedDocument,
@@ -13,7 +15,6 @@ from mongoengine import (
 )
 
 from tests.utils import MongoDBTestCase
-import pytest
 
 
 class TestEmbeddedDocumentField(MongoDBTestCase):
diff --git a/tests/fields/test_fields.py b/tests/fields/test_fields.py
index 21cc78be..b8c916f8 100644
--- a/tests/fields/test_fields.py
+++ b/tests/fields/test_fields.py
@@ -4,6 +4,7 @@ import unittest
 
 from bson import DBRef, ObjectId, SON
 from nose.plugins.skip import SkipTest
+import pytest
 
 from mongoengine import (
     BooleanField,
@@ -39,7 +40,6 @@ from mongoengine.base import BaseField, EmbeddedDocumentList, _document_registry
 from mongoengine.errors import DeprecatedError
 
 from tests.utils import MongoDBTestCase
-import pytest
 
 
 class TestField(MongoDBTestCase):
@@ -1838,7 +1838,7 @@ class TestField(MongoDBTestCase):
 
         user = User.objects(bookmarks__all=[post_1]).first()
 
-        assert user != None
+        assert user is not None
         assert user.bookmarks[0] == post_1
 
     def test_generic_reference_filter_by_dbref(self):
diff --git a/tests/fields/test_file_field.py b/tests/fields/test_file_field.py
index 0746db33..fb8cacff 100644
--- a/tests/fields/test_file_field.py
+++ b/tests/fields/test_file_field.py
@@ -137,7 +137,6 @@ class TestFileField(MongoDBTestCase):
 
         text = six.b("Hello, World!")
         more_text = six.b("Foo Bar")
-        content_type = "text/plain"
 
         streamfile = StreamFile()
         streamfile.save()
@@ -205,7 +204,7 @@ class TestFileField(MongoDBTestCase):
             doc_b = GridDocument.objects.with_id(doc_a.id)
             doc_b.the_file.replace(f, filename="doc_b")
             doc_b.save()
-            assert doc_b.the_file.grid_id != None
+            assert doc_b.the_file.grid_id is not None
 
             # Test it matches
             doc_c = GridDocument.objects.with_id(doc_b.id)
diff --git a/tests/fields/test_float_field.py b/tests/fields/test_float_field.py
index d755fb4e..a1cd7a0a 100644
--- a/tests/fields/test_float_field.py
+++ b/tests/fields/test_float_field.py
@@ -1,10 +1,10 @@
 # -*- coding: utf-8 -*-
+import pytest
 import six
 
 from mongoengine import *
 
 from tests.utils import MongoDBTestCase
-import pytest
 
 
 class TestFloatField(MongoDBTestCase):
diff --git a/tests/fields/test_int_field.py b/tests/fields/test_int_field.py
index 65a5fbad..1f9c5a77 100644
--- a/tests/fields/test_int_field.py
+++ b/tests/fields/test_int_field.py
@@ -1,8 +1,9 @@
 # -*- coding: utf-8 -*-
+import pytest
+
 from mongoengine import *
 
 from tests.utils import MongoDBTestCase
-import pytest
 
 
 class TestIntField(MongoDBTestCase):
diff --git a/tests/fields/test_lazy_reference_field.py b/tests/fields/test_lazy_reference_field.py
index 8150574d..b5b8690e 100644
--- a/tests/fields/test_lazy_reference_field.py
+++ b/tests/fields/test_lazy_reference_field.py
@@ -1,11 +1,11 @@
 # -*- coding: utf-8 -*-
 from bson import DBRef, ObjectId
+import pytest
 
 from mongoengine import *
 from mongoengine.base import LazyReference
 
 from tests.utils import MongoDBTestCase
-import pytest
 
 
 class TestLazyReferenceField(MongoDBTestCase):
diff --git a/tests/fields/test_long_field.py b/tests/fields/test_long_field.py
index 51f8e255..da4f04c8 100644
--- a/tests/fields/test_long_field.py
+++ b/tests/fields/test_long_field.py
@@ -1,4 +1,5 @@
 # -*- coding: utf-8 -*-
+import pytest
 import six
 
 try:
@@ -10,7 +11,6 @@ from mongoengine import *
 from mongoengine.connection import get_db
 
 from tests.utils import MongoDBTestCase
-import pytest
 
 
 class TestLongField(MongoDBTestCase):
diff --git a/tests/fields/test_map_field.py b/tests/fields/test_map_field.py
index fd56ddd0..8b8b1c46 100644
--- a/tests/fields/test_map_field.py
+++ b/tests/fields/test_map_field.py
@@ -1,11 +1,11 @@
 # -*- coding: utf-8 -*-
 import datetime
 
-from mongoengine import *
-
-from tests.utils import MongoDBTestCase
 import pytest
 
+from mongoengine import *
+from tests.utils import MongoDBTestCase
+
 
 class TestMapField(MongoDBTestCase):
     def test_mapfield(self):
diff --git a/tests/fields/test_reference_field.py b/tests/fields/test_reference_field.py
index 783d1315..949eac67 100644
--- a/tests/fields/test_reference_field.py
+++ b/tests/fields/test_reference_field.py
@@ -1,10 +1,9 @@
 # -*- coding: utf-8 -*-
 from bson import DBRef, SON
+import pytest
 
 from mongoengine import *
-
 from tests.utils import MongoDBTestCase
-import pytest
 
 
 class TestReferenceField(MongoDBTestCase):
@@ -59,21 +58,6 @@ class TestReferenceField(MongoDBTestCase):
         with pytest.raises(ValidationError):
             post1.validate()
 
-    def test_objectid_reference_fields(self):
-        """Make sure storing Object ID references works."""
-
-        class Person(Document):
-            name = StringField()
-            parent = ReferenceField("self")
-
-        Person.drop_collection()
-
-        p1 = Person(name="John").save()
-        Person(name="Ross", parent=p1.pk).save()
-
-        p = Person.objects.get(name="Ross")
-        assert p.parent == p1
-
     def test_dbref_reference_fields(self):
         """Make sure storing references as bson.dbref.DBRef works."""
 
diff --git a/tests/fields/test_url_field.py b/tests/fields/test_url_field.py
index e125f56a..948a4788 100644
--- a/tests/fields/test_url_field.py
+++ b/tests/fields/test_url_field.py
@@ -1,8 +1,9 @@
 # -*- coding: utf-8 -*-
+import pytest
+
 from mongoengine import *
 
 from tests.utils import MongoDBTestCase
-import pytest
 
 
 class TestURLField(MongoDBTestCase):
diff --git a/tests/fields/test_uuid_field.py b/tests/fields/test_uuid_field.py
index b1413f95..21b7a090 100644
--- a/tests/fields/test_uuid_field.py
+++ b/tests/fields/test_uuid_field.py
@@ -1,11 +1,11 @@
 # -*- coding: utf-8 -*-
 import uuid
 
-from mongoengine import *
-
-from tests.utils import MongoDBTestCase, get_as_pymongo
 import pytest
 
+from mongoengine import *
+from tests.utils import MongoDBTestCase, get_as_pymongo
+
 
 class Person(Document):
     api_key = UUIDField(binary=False)
diff --git a/tests/fixtures.py b/tests/fixtures.py
index 9f06f1ab..59fc3bf3 100644
--- a/tests/fixtures.py
+++ b/tests/fixtures.py
@@ -42,11 +42,11 @@ class PickleSignalsTest(Document):
 
     @classmethod
     def post_save(self, sender, document, created, **kwargs):
-        pickled = pickle.dumps(document)
+        pickle.dumps(document)
 
     @classmethod
     def post_delete(self, sender, document, **kwargs):
-        pickled = pickle.dumps(document)
+        pickle.dumps(document)
 
 
 signals.post_save.connect(PickleSignalsTest.post_save, sender=PickleSignalsTest)
diff --git a/tests/queryset/test_field_list.py b/tests/queryset/test_field_list.py
index a2bf6f1f..fbdde23b 100644
--- a/tests/queryset/test_field_list.py
+++ b/tests/queryset/test_field_list.py
@@ -1,8 +1,9 @@
 import unittest
 
+import pytest
+
 from mongoengine import *
 from mongoengine.queryset import QueryFieldList
-import pytest
 
 
 class TestQueryFieldList(unittest.TestCase):
@@ -221,7 +222,7 @@ class TestOnlyExcludeAll(unittest.TestCase):
         assert obj.comments == []
 
         obj = BlogPost.objects.only("various.test_dynamic.some").get()
-        assert obj.various["test_dynamic"].some == True
+        assert obj.various["test_dynamic"].some is True
 
         obj = BlogPost.objects.only("content", "comments.title").get()
         assert obj.content == "Had a good coffee today..."
diff --git a/tests/queryset/test_queryset.py b/tests/queryset/test_queryset.py
index f3606609..79f5793d 100644
--- a/tests/queryset/test_queryset.py
+++ b/tests/queryset/test_queryset.py
@@ -9,6 +9,7 @@ from bson import DBRef, ObjectId
 import pymongo
 from pymongo.read_preferences import ReadPreference
 from pymongo.results import UpdateResult
+import pytest
 import six
 from six import iteritems
 
@@ -24,7 +25,6 @@ from mongoengine.queryset import (
     QuerySetManager,
     queryset_manager,
 )
-import pytest
 
 
 class db_ops_tracker(query_counter):
@@ -1712,11 +1712,11 @@ class TestQueryset(unittest.TestCase):
         post = BlogPost(content="Watching TV", category=lameness)
         post.save()
 
-        assert 1 == BlogPost.objects.count()
-        assert "Lameness" == BlogPost.objects.first().category.name
+        assert BlogPost.objects.count() == 1
+        assert BlogPost.objects.first().category.name == "Lameness"
         Category.objects.delete()
-        assert 1 == BlogPost.objects.count()
-        assert None == BlogPost.objects.first().category
+        assert BlogPost.objects.count() == 1
+        assert BlogPost.objects.first().category is None
 
     def test_reverse_delete_rule_nullify_on_abstract_document(self):
         """Ensure nullification of references to deleted documents when
@@ -1739,11 +1739,11 @@ class TestQueryset(unittest.TestCase):
 
         BlogPost(content="Watching TV", author=me).save()
 
-        assert 1 == BlogPost.objects.count()
-        assert me == BlogPost.objects.first().author
+        assert BlogPost.objects.count() == 1
+        assert BlogPost.objects.first().author == me
         self.Person.objects(name="Test User").delete()
-        assert 1 == BlogPost.objects.count()
-        assert None == BlogPost.objects.first().author
+        assert BlogPost.objects.count() == 1
+        assert BlogPost.objects.first().author is None
 
     def test_reverse_delete_rule_deny(self):
         """Ensure deletion gets denied on documents that still have references
@@ -1896,7 +1896,7 @@ class TestQueryset(unittest.TestCase):
         """
         p1 = self.Person(name="User Z", age=20).save()
         del_result = p1.delete(w=0)
-        assert None == del_result
+        assert del_result is None
 
     def test_reference_field_find(self):
         """Ensure cascading deletion of referring documents from the database.
@@ -2047,7 +2047,7 @@ class TestQueryset(unittest.TestCase):
 
         post = BlogPost(title="garbage").save()
 
-        assert post.title != None
+        assert post.title is not None
         BlogPost.objects.update_one(unset__title=1)
         post.reload()
         assert post.title is None
@@ -5006,7 +5006,7 @@ class TestQueryset(unittest.TestCase):
                 # PyPy evaluates __len__ when iterating with list comprehensions while CPython does not.
                 # This may be a bug in PyPy (PyPy/#1802) but it does not affect
                 # the behavior of MongoEngine.
-                assert None == people._len
+                assert people._len is None
             assert q == 1
 
             list(people)
@@ -5053,7 +5053,7 @@ class TestQueryset(unittest.TestCase):
         Person(name="a").save()
         qs = Person.objects()
         _ = list(qs)
-        with pytest.raises(OperationError, match="QuerySet already cached") as ctx_err:
+        with pytest.raises(OperationError, match="QuerySet already cached"):
             qs.no_cache()
 
     def test_no_cached_queryset_no_cache_back_to_cache(self):
diff --git a/tests/queryset/test_transform.py b/tests/queryset/test_transform.py
index be28c3b8..3898809e 100644
--- a/tests/queryset/test_transform.py
+++ b/tests/queryset/test_transform.py
@@ -1,10 +1,10 @@
 import unittest
 
 from bson.son import SON
+import pytest
 
 from mongoengine import *
 from mongoengine.queryset import Q, transform
-import pytest
 
 
 class TestTransform(unittest.TestCase):
diff --git a/tests/queryset/test_visitor.py b/tests/queryset/test_visitor.py
index 9706d012..e597e3d8 100644
--- a/tests/queryset/test_visitor.py
+++ b/tests/queryset/test_visitor.py
@@ -3,11 +3,11 @@ import re
 import unittest
 
 from bson import ObjectId
+import pytest
 
 from mongoengine import *
 from mongoengine.errors import InvalidQueryError
 from mongoengine.queryset import Q
-import pytest
 
 
 class TestQ(unittest.TestCase):
diff --git a/tests/test_connection.py b/tests/test_connection.py
index 8db69b0c..07edcbba 100644
--- a/tests/test_connection.py
+++ b/tests/test_connection.py
@@ -3,10 +3,10 @@ import datetime
 from bson.tz_util import utc
 from nose.plugins.skip import SkipTest
 import pymongo
-from pymongo import MongoClient
-from pymongo import ReadPreference
-from pymongo.errors import InvalidName, OperationFailure
 
+from pymongo import MongoClient, ReadPreference
+from pymongo.errors import InvalidName, OperationFailure
+import pytest
 
 try:
     import unittest2 as unittest
@@ -29,7 +29,6 @@ from mongoengine.connection import (
     get_connection,
     get_db,
 )
-import pytest
 
 
 def get_tz_awareness(connection):
diff --git a/tests/test_context_managers.py b/tests/test_context_managers.py
index cf4dd100..d68afbb0 100644
--- a/tests/test_context_managers.py
+++ b/tests/test_context_managers.py
@@ -1,5 +1,7 @@
 import unittest
 
+import pytest
+
 from mongoengine import *
 from mongoengine.connection import get_db
 from mongoengine.context_managers import (
@@ -10,7 +12,6 @@ from mongoengine.context_managers import (
     switch_db,
 )
 from mongoengine.pymongo_support import count_documents
-import pytest
 
 
 class ContextManagersTest(unittest.TestCase):
@@ -214,7 +215,6 @@ class ContextManagersTest(unittest.TestCase):
                 raise TypeError()
 
     def test_query_counter_does_not_swallow_exception(self):
-
         with pytest.raises(TypeError):
             with query_counter() as q:
                 raise TypeError()
diff --git a/tests/test_datastructures.py b/tests/test_datastructures.py
index 24cda40d..ad421a72 100644
--- a/tests/test_datastructures.py
+++ b/tests/test_datastructures.py
@@ -1,7 +1,7 @@
 import unittest
-from six import iterkeys
 
 import pytest
+from six import iterkeys
 
 from mongoengine import Document
 from mongoengine.base.datastructures import BaseDict, BaseList, StrictDict
diff --git a/tests/test_replicaset_connection.py b/tests/test_replicaset_connection.py
index c1ea407c..5d83da00 100644
--- a/tests/test_replicaset_connection.py
+++ b/tests/test_replicaset_connection.py
@@ -1,7 +1,6 @@
 import unittest
 
-from pymongo import MongoClient
-from pymongo import ReadPreference
+from pymongo import MongoClient, ReadPreference
 
 import mongoengine
 from mongoengine.connection import ConnectionFailure
@@ -25,14 +24,13 @@ class ConnectionTest(unittest.TestCase):
     def test_replicaset_uri_passes_read_preference(self):
         """Requires a replica set called "rs" on port 27017
         """
-
         try:
             conn = mongoengine.connect(
                 db="mongoenginetest",
                 host="mongodb://localhost/mongoenginetest?replicaSet=rs",
                 read_preference=READ_PREF,
             )
-        except ConnectionFailure as e:
+        except ConnectionFailure:
             return
 
         if not isinstance(conn, CONN_CLASS):
diff --git a/tests/test_utils.py b/tests/test_utils.py
index ccb44aac..ef396571 100644
--- a/tests/test_utils.py
+++ b/tests/test_utils.py
@@ -1,9 +1,10 @@
 import re
 import unittest
 
-from mongoengine.base.utils import LazyRegexCompiler
 import pytest
 
+from mongoengine.base.utils import LazyRegexCompiler
+
 signal_output = []