tracker: actually test thumbnails

Reviewers: smcv, pwith

Differential Revision: https://phabricator.apertis.org/D393

tracker/automated/test-tracker.py

@@ -181,6 +181,7 @@ class TrackerTest(unittest.TestCase):
         self.tracker_inital_tests()
         self.tracker_update_tests()
         self.tracker_grilo_tests()
+        self.thumbnail_tests()
 
 if __name__ == "__main__":
     Grl.init([])