--- a/testing/marionette/harness/marionette/tests/unit/test_session.py
+++ b/testing/marionette/harness/marionette/tests/unit/test_session.py
@@ -26,24 +26,24 @@ class TestSession(MarionetteTestCase):
         # Optional capabilities we want Marionette to support
         self.assertIn("device", caps)
         self.assertIn("rotatable", caps)
         self.assertIn("takesScreenshot", caps)
         self.assertIn("version", caps)
 
     def test_we_can_get_the_session_id(self):
         # Sends newSession
-        caps = self.marionette.start_session()
+        self.marionette.start_session()
 
         self.assertTrue(self.marionette.session_id is not None)
         self.assertTrue(isinstance(self.marionette.session_id, unicode))
 
     def test_we_can_set_the_session_id(self):
         # Sends newSession
-        caps = self.marionette.start_session(session_id="ILoveCheese")
+        self.marionette.start_session(session_id="ILoveCheese")
 
         self.assertEqual(self.marionette.session_id, "ILoveCheese")
         self.assertTrue(isinstance(self.marionette.session_id, unicode))
 
     def test_we_only_support_one_active_session_at_a_time(self):
         self.marionette.start_session()
         self.assertTrue(isinstance(self.marionette.session_id, unicode))
         self.assertRaises(SessionNotCreatedException, self.marionette._send_message, "newSession", {})