Properly testing an OTP application after initialization

Hello list,

I'm writing an OTP application that has many things I would like to
test _after_ my application has started. The way I'm currently testing
is to wrap eunit in a utility function that I invoke in the shell,
which then goes through and does all sorts of stateful things against
my gen_servers and reports back. This seems to work okay, but seems
incompatible with e.g. 'rebar3 eunit' and generally seems like it may
not be the intended way to use the tool.

Now that I want to start wiring the testing framework up to my CI
tool, I am wondering if I should do something like start my
application, connect a shell to it, run my tests, and shut down? or
should I take a step back entirely and consider using something like
Common Test instead?

Thanks much,
Lincoln