DR-243. One set of behaviours every engine must satisfy, written before the
second engine exists so it cannot encode whatever the first happens to do —
which is how three playback implementations drifted apart in the first place.
FakePlayer models the one behaviour that matters most: opening is not
instantaneous. `open` parks in Phase::Opening until complete_open() is called,
so a test can put a seek into that window deliberately. That window is where
DR-241 lived, and it was previously unreachable from any test.
The suite drives readiness through a Harness rather than sleeping — the fake
completes on demand, a real engine waits for its own readiness event. A
timing-dependent suite is worse than none, because it teaches people to
re-run until green.
Nine cases, each naming the defect it prevents:
opens_at_a_start_position DR-241 - starts there, never at zero
seek_while_opening_is_honoured DR-241 - held, not discarded
seek_while_opening_overrides_start later intent wins
pause_and_play_are_observable DR-239 - state an engine cannot hide
close_is_silent_and_idempotent stopped must mean silent
close_during_open_never_plays an open cancelled by close
must not come back to life
`audible()` may return None for engines that cannot answer, which skips the
silence assertions rather than passing them vacuously — an assertion that
cannot fail is worse than an absent one.
Also adds MediaItem::sample: the struct has twenty-odd fields, almost none of
which a given test cares about, and repeating the literal per test is how a
new field ends up added in thirty places.
dtourolle
f4892f4cb2