diff --git a/mayan/settings/testing/base.py b/mayan/settings/testing/base.py
index 756a9efd1b..617da6cd62 100644
--- a/mayan/settings/testing/base.py
+++ b/mayan/settings/testing/base.py
@@ -3,7 +3,10 @@ from __future__ import absolute_import, unicode_literals
 from .. import *  # NOQA
 
 INSTALLED_APPS += ('test_without_migrations',)
-INSTALLED_APPS -= ('whitenoise.runserver_nostatic',)
+
+INSTALLED_APPS = [
+    cls for cls in INSTALLED_APPS if cls != 'whitenoise.runserver_nostatic'
+]
 
 COMMON_PRODUCTION_ERROR_LOG_PATH = '/tmp/mayan-errors.log'
 
@@ -15,7 +18,7 @@ TEMPLATES[0]['OPTIONS']['loaders'] = (
 # Remove whitenoise from middlewares. Causes out of memory errors during test
 # suit
 MIDDLEWARE_CLASSES = [
-    cls for cls in MIDDLEWARE_CLASSES if cls !='whitenoise.middleware.WhiteNoiseMiddleware'
+    cls for cls in MIDDLEWARE_CLASSES if cls != 'whitenoise.middleware.WhiteNoiseMiddleware'
 ]
 
 STATICFILES_STORAGE = None