Traceback (most recent call last):
  File "/home/phablet/src/unity8-shellRotation/tests/autopilot/unity8/shell/tests/test_rotation.py", line 70, in test_rotation
    print ("orientation-angle: ", self.main_window.get_shell_orientation_angle())
  File "/home/phablet/src/unity8-shellRotation/tests/autopilot/unity8/shell/tests/__init__.py", line 393, in main_window
    return self._proxy.select_single(main_window_emulator.QQuickView)
AttributeError: 'NoneType' object has no attribute 'select_single'