tonihei 342be88d81 Improve playlist operation behavior of session test MockPlayer
The MockPlayer currently:
 - uses separate fields for single mediaItem vs multiple mediaItems
 - replaces all items on addMediaItem operations
 - does nothing on remove/move operations.

Fix all of this by using a single field that replicates the player
operations directly.

Some tests also need to be updated to make them more realistic
(for example only removing items from a playlist that have
previously been added).

PiperOrigin-RevId: 451857271
2022-05-30 16:47:44 +00:00
..
2021-10-27 09:12:46 +01:00