Finally caught with a creation stack trace: when the last gRPC
stream closes, Http2ClientConnection arms the channel's 5-minute
idleTimeout timer — even on a shut-down connection — so the
test's 1-minute drain never covered it and the framework's
pending-timer invariant tripped whenever the arm landed inside
the test window (frequent while a real hub listens on 50051).
The suite now closes the channel in real-async space at the end
of the body (new @visibleForTesting HubService.debugResetChannel;
shutdown is deliberately not awaited — it wedges on a mid-connect
socket, but cancels its timers synchronously) and pumps past the
idle timeout so the timer fires inside the test. 6 consecutive
full-suite runs + 3 isolated runs green; before, roughly 1 in 3
full runs failed.
Signed-off-by: flemming-it <stefan.a.flemming@googlemail.com>
c18bb7f357