I'm trying to add new test cases for when resuming backgrounded videos is allowed and it seems very hard to read and modify the tests.

There's a separate class (test fixture) for every test case with lots of similar protected methods in the base class. Seems like the test fixtures are different to setup the command line differently for each combination of unified pipeline & disable media suspend. Could we just setup the necessary parameters at the beginning of the test case?

TestSessionXWhenY should also be one method with parameters (could we make MediaSession::State public for tests?).