When I went to install it, it asked if I wanted to "update" an existing app on my phone, so the package name of this test app is probably the default b4a.example.
And since I don't remember what other app on my phone is currently using that package name, I don't know which app to uninstall first because when I still try to install this one, it fails - probably because of the version/key conflict.
Can you repost the test app with a unique package name so I can install it?