added DiscoverRunner for django 1.7 and above

tests/settings.py

@@ -1,5 +1,6 @@
 # Django settings for example project.
 import os
+from django import VERSION as DJANGO_VERSION
 
 DEBUG = True
 TEMPLATE_DEBUG = DEBUG
@@ -68,3 +69,8 @@ MIDDLEWARE_CLASSES = (
     'django.contrib.messages.middleware.MessageMiddleware',
     'django.middleware.clickjacking.XFrameOptionsMiddleware',
 )
+
+# Use DiscoverRunner on Django 1.7 and above
+if DJANGO_VERSION[0] == 1 and DJANGO_VERSION[1] >= 7:
+    TEST_RUNNER = 'django.test.runner.DiscoverRunner'
+