diff --git a/.flake8 b/.flake8
new file mode 100644
index 0000000..6deafc2
--- /dev/null
+++ b/.flake8
@@ -0,0 +1,2 @@
+[flake8]
+max-line-length = 120
diff --git a/drf_extra_fields/fields.py b/drf_extra_fields/fields.py
index 3687a95..5e20963 100644
--- a/drf_extra_fields/fields.py
+++ b/drf_extra_fields/fields.py
@@ -17,7 +17,7 @@
     ImageField,
     IntegerField,
 )
-from rest_framework.utils import html, humanize_datetime, representation
+from rest_framework.utils import html
 from .compat import (
     DateRange,
     DateTimeTZRange,
@@ -196,6 +196,7 @@ class DateRangeField(RangeField):
     child = DateField()
     range_type = DateRange
 
+
 if postgres_fields is not None:
     # monkey patch modelserializer to map Native django Range fields to
     # drf_extra_fiels's Range fields.
diff --git a/drf_extra_fields/runtests/settings.py b/drf_extra_fields/runtests/settings.py
index f53d8fe..37754ec 100644
--- a/drf_extra_fields/runtests/settings.py
+++ b/drf_extra_fields/runtests/settings.py
@@ -1,3 +1,6 @@
+import os
+import django
+
 # Django settings for testproject project.
 
 DEBUG = True
@@ -14,7 +17,7 @@
 
 DATABASES = {
     'default': {
-        'ENGINE': 'django.db.backends.sqlite3',  # Add 'postgresql_psycopg2', 'postgresql', 'mysql', 'sqlite3' or 'oracle'.
+        'ENGINE': 'django.db.backends.sqlite3',  # Add 'postgresql', 'mysql', 'sqlite3' or 'oracle'.
         'NAME': 'sqlite.db',                     # Or path to database file if using sqlite3.
         'USER': '',                      # Not used with sqlite3.
         'PASSWORD': '',                  # Not used with sqlite3.
@@ -68,7 +71,7 @@
 TEMPLATE_LOADERS = (
     'django.template.loaders.filesystem.Loader',
     'django.template.loaders.app_directories.Loader',
-#     'django.template.loaders.eggs.Loader',
+    # 'django.template.loaders.eggs.Loader',
 )
 
 MIDDLEWARE_CLASSES = (
@@ -105,42 +108,6 @@
     # 'rest_framework.tests.users',
 )
 
-# OAuth is optional and won't work if there is no oauth_provider & oauth2
-try:
-    import oauth_provider
-    import oauth2
-except ImportError:
-    pass
-else:
-    INSTALLED_APPS += (
-        'oauth_provider',
-    )
-
-try:
-    import provider
-except ImportError:
-    pass
-else:
-    INSTALLED_APPS += (
-        'provider',
-        'provider.oauth2',
-    )
-
-# guardian is optional
-try:
-    import guardian
-except ImportError:
-    pass
-else:
-    ANONYMOUS_USER_ID = -1
-    AUTHENTICATION_BACKENDS = (
-        'django.contrib.auth.backends.ModelBackend', # default
-        'guardian.backends.ObjectPermissionBackend',
-    )
-    INSTALLED_APPS += (
-        'guardian',
-    )
-
 STATIC_URL = '/static/'
 
 PASSWORD_HASHERS = (
@@ -154,13 +121,10 @@
 
 AUTH_USER_MODEL = 'auth.User'
 
-import django
-
 if django.VERSION < (1, 3):
     INSTALLED_APPS += ('staticfiles',)
 
 # If we're running on the Jenkins server we want to archive the coverage reports as XML.
-import os
 if os.environ.get('HUDSON_URL', None):
     TEST_RUNNER = 'xmlrunner.extra.djangotestrunner.XMLTestRunner'
     TEST_OUTPUT_VERBOSE = True
diff --git a/requirements.txt b/requirements.txt
index 5df405c..24b87de 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,3 +1,5 @@
 Django >= 1.4
 djangorestframework >= 3.0.1
-pillow
\ No newline at end of file
+pillow
+flake8
+mock
\ No newline at end of file
diff --git a/tests/test_fields.py b/tests/test_fields.py
index ed1315e..be42565 100644
--- a/tests/test_fields.py
+++ b/tests/test_fields.py
@@ -5,8 +5,7 @@
 import django
 from django.core.exceptions import ValidationError
 from django.test import TestCase, override_settings
-from django.db import models
-from mock import MagicMock, patch
+from mock import patch
 import pytz
 from rest_framework import serializers
 
@@ -145,6 +144,7 @@ def test_hybrid_image_field(self):
                 self.assertTrue(mixin_patch.to_internal_value.called)
                 self.assertTrue(image_patch.to_internal_value.called)
 
+
 class PDFBase64FileField(Base64FileField):
     ALLOWED_TYPES = ('pdf',)
 
@@ -194,19 +194,16 @@ def test_create_with_base64_prefix(self):
         self.assertEqual(serializer.validated_data['created'], uploaded_file.created)
         self.assertFalse(serializer.validated_data is uploaded_file)
 
-
     def test_validation_error_with_non_file(self):
         """
         Passing non-base64 should raise a validation error.
         """
         now = datetime.datetime.now()
         errmsg = "Please upload a valid file."
-        serializer = UploadedBase64FileSerializer(data={'created': now,
-                                                         'file': 'abc'})
+        serializer = UploadedBase64FileSerializer(data={'created': now, 'file': 'abc'})
         self.assertFalse(serializer.is_valid())
         self.assertEqual(serializer.errors, {'file': [errmsg]})
 
-
     def test_remove_with_empty_string(self):
         """
         Passing empty string as data should cause file to be removed
@@ -309,8 +306,8 @@ def test_invalid_latitude(self):
         serializer = PointSerializer(data={'created': now, 'point': point})
         self.assertFalse(serializer.is_valid())
 
-# Backported from django_rest_framework/tests/test_fields.py
 
+# Backported from django_rest_framework/tests/test_fields.py
 def get_items(mapping_or_list_of_two_tuples):
     # Tests accept either lists of two tuples, or dictionaries.
     if isinstance(mapping_or_list_of_two_tuples, dict):
diff --git a/tests/test_relations.py b/tests/test_relations.py
index 1490fad..71264fe 100644
--- a/tests/test_relations.py
+++ b/tests/test_relations.py
@@ -1,5 +1,3 @@
-import pytest
-
 from rest_framework import serializers
 from rest_framework.test import APISimpleTestCase
 from .utils import (
diff --git a/tox.ini b/tox.ini
index 6a076d7..f724d28 100644
--- a/tox.ini
+++ b/tox.ini
@@ -9,4 +9,7 @@ deps =
     pytest-django
     psycopg2
     mock
-commands = py.test {posargs}
+    flake8
+commands =
+    py.test {posargs}
+    flake8