Ask HN: Uptime monitor for mobile apps?

Friend's B2B SaaS company has a lightly-used Android app. The login screen stopped working, and nobody knew about it for several days.

I know there are plenty of uptime monitors for servers / websites, but are there any uptime monitors for mobile apps? Something that lets you say "here's our app store URL, here's a dummy account login - can you make sure you can download the app, log in, and access all the menu options?"