Also show warning via coverage and travis

runtests.py

@@ -1,5 +1,6 @@
 #!/usr/bin/env python -Wd
 import sys
+import warnings
 from os.path import abspath, dirname
 
 import dj_database_url
@@ -7,6 +8,8 @@ import django
 from django.conf import settings
 from django.core.management import execute_from_command_line
 
+# python -Wd, or run via coverage:
+warnings.simplefilter('always', DeprecationWarning)
 
 # Give feedback on used versions
 sys.stderr.write('Using Python version {0} from {1}\n'.format(sys.version[:5], sys.executable))