Usually this would be handled by `TextureAnimation`, but because we are
inheriting from `DrawableAnimation` here for reasons, we needed to
implement this ourselves. Follows the implementation in
`TextureAnimation`.
Due to the logic present to handle `@2x` fallback, the extension was
potentially being added at the wrong point in the filename. This change
ensures that the lookup filenames are always correct.
Closes https://github.com/ppy/osu/issues/17690.
A lot of tests are using test resources that populate the length field,
but do not populate hitobjects. The general expectation is that
components should be using the cached length in cases where hitobjects
are not relevant, but `GetVirtualTrack` was doing its own local
calculation.
This could cause tests to fail due to `MusicController` changing track
in the background.
The import process was running on the async load thread, but then
accessed from the access thread later on. This seemed to somehow pass
fine in headless runs, but would fail on visual test execution
(specifically on `TestBeatmapConfirmed()`).