xUnit v2 (2.9.3) never invokes IAsyncDisposable.DisposeAsync on a test
class, so the unobserved-fault safety net this class documents — awaiting
every scripted worker task after each test — has been dead code since it
was written. Found via dumpasync on the wedged-testhost investigation: the
NeverReadyWorkerProcessLauncher's Task.Delay(Infinite, _stop.Token) was
still pending (DelayPromiseWithCancellation, detached) minutes after its
test finished, which is only possible if DisposeAsync never ran.
Proven both ways with a throw-probe in DisposeAsync: under IAsyncDisposable
all 3 tests pass (never called); under IAsyncLifetime all 3 fail from the
probe (called after every test). Sweep confirmed this is the only test
class on IAsyncDisposable — all other implementers are helpers disposed
via await using.
Joseph Doherty
3e504ca9c4