Provide tools to test a player

[MGaetan89]

Pull request

Description

This PR aims to provide some tools to be able to easily test a player.

Changes made

• Created a PlayerIdlingResource to wait until the player under test reaches a specific state
• Created an ExoPlayerRule that setup the player
• Created TestSimpleProgressTrackerState to show how to use these two new classes

Warning

This PR is in draft because for the moment the player under test remains in the buffering state. Once this is fixed (and probably TestSimpleProgressTrackerState too), PlayerIdlingResource and ExoPlayerRule can be moved to pillarbox-player-testutils.

Note

These new classes are only necessary when we need to directly access the player. Otherwise, ExoPlayerTestRunner from media3-test-utils is probably a better solution, as it already takes care of setting up the player, handling state change, and providing various assertions. ExoPlayerTest shows various examples of how to use that class (look for ExoPlayerTestRunner.Builder).

Checklist

• Your branch has been rebased onto the main branch.
• APIs have been properly documented (if relevant).
• The documentation has been updated (if relevant).
• New unit tests have been written (if relevant).
• The demo has been updated (if relevant).
• All pull request status checks pass.