Make django tests work properly on Travis.

.travis.yml

@@ -14,7 +14,7 @@ script:
   - if [ -n "$DJANGO_VERSION" ]; then
       coverage run --source=optimize_later testproject/manage.py test;
     else
-      coverage run --source=optimize_later -m unittest optimize_later.tests;
+      coverage run --source=optimize_later -m unittest discover optimize_later/;
     fi
 after_script:
   - codecov

optimize_later/tests/test_django.py

@@ -5,10 +5,13 @@ import uuid
 from optimize_later.core import optimize_later, OptimizeReport
 
 try:
-    import django
+    from django.conf import settings
 except ImportError:
-    pass
+    use_django = False
 else:
+    use_django = settings.configured
+
+if use_django:
     from django.test import TestCase
     from optimize_later import apps
 

testproject/testproject/settings.py

@@ -38,7 +38,6 @@ INSTALLED_APPS = [
     'django.contrib.messages',
     'django.contrib.staticfiles',
     'optimize_later',
-    'testapp',
 ]
 
 MIDDLEWARE = [