ref(tests): use assertContains() instead of assertEquals

In Python 3, Django's HTTPResponse.content contains bytes, which
becomes an issue if comparing against a string in tests. The
preferred solution is to rely on assertContains() and assertNotContains().

See https://docs.djangoproject.com/es/1.9/topics/python3/#httprequest-and-httpresponse-objects

Author: Matthew Fisher

rootfs/api/tests/test_app.py

@@ -109,20 +109,20 @@ def test_app_actions(self, mock_requests, mock_get):
         mock_response.status_code = 400
         response = self.client.get(url)
         self.assertEqual(response.status_code, 500)
-        self.assertEqual(response.content, "Error accessing logs for {}".format(app_id))
+        self.assertContains(response, "Error accessing logs for {}".format(app_id))
 
         # test logs - success accessing deis-logger
         mock_response.status_code = 200
         mock_response.content = FAKE_LOG_DATA
         response = self.client.get(url)
         self.assertEqual(response.status_code, 200)
-        self.assertEqual(response.content, FAKE_LOG_DATA)
+        self.assertContains(response, FAKE_LOG_DATA)
 
         # test logs - HTTP request error while accessing deis-logger
         mock_get.side_effect = requests.exceptions.RequestException('Boom!')
         response = self.client.get(url)
         self.assertEqual(response.status_code, 500)
-        self.assertEqual(response.content, "Error accessing logs for {}".format(app_id))
+        self.assertContains(response, "Error accessing logs for {}".format(app_id))
 
         # TODO: test run needs an initial build