Random T-Mobile Diagnostics message of "test"

Something I find interesting is that I have the the Tmobile Diagnostic disabled. So even if this was a test, it should not have been able to bypass and post. Can you tell me what the heck this thing is really doing in the background if I hadn't given it permission via that app to do so in the first place. Getting really tired of apps saying they are doing one thing, like when you say NO do not listen, do not activate my camera and so on, and they still keep doing it anyway...