Fix spurious content-ty on 304; xfail css Cache-Control Using wsgiref.validate.validator to verify http/wsgi responses. It discovered that a 304 was returning a content-type header but shouldn't. Fixed that. For some unknown reason I can't reproduce on my devel platform, travis-ci is throwing: > self.assertEqual(f.headers['Cache-Control'], 'public, max-age=4838400') E AssertionError: 'public, max-age=3600' != 'public, max-age=4838400' E - public, max-age=3600 E ? ^ E + public, max-age=4838400 E ? ++ ^^ in test_liveserver test_cache_control_css. I have no idea why this is happening. The 3600 value isn't in the code base or tracker template that I see. While I was trying to figure out if the wsgi server later was an issue, I came across the validator. Maybe it will throw some light on this error?