Addon Manager: Add tests for Addon

src/Mod/AddonManager/TestAddonManagerApp.py

@@ -26,6 +26,10 @@
 from AddonManagerTest.app.test_utilities import (
     TestUtilities as AddonManagerTestUtilities,
 )
+from AddonManagerTest.app.test_addon import (
+    TestAddon as AddonManagerTestAddon,
+)
 
 # dummy usage to get flake8 and lgtm quiet
 False if AddonManagerTestUtilities.__name__ else True
+False if AddonManagerTestAddon.__name__ else True