Is it possible to fetch test packages from test .apk or installed .apk?

I am looking for solution to list up all possible tests that can be run via installed/generated test .*apk. Does any know solution how to do it from command line?

To say something more:

When we look at Instrumentation Runner documentation we can see that to run all tests we have to use this command:

Running all tests: adb shell am instrument -w http://ift.tt/1Nxfw2s

And there is nothing about either application .*apk or test .*apk. But you have to insert package. So when you see process running then test packages are mentioned and used. So from where did Instrumentation Runner get it? Is there any command to check what packages are included in installed test package which runs against application package?