The test started a sidecar and an engine, each a shell appending its name to a
file, and demanded the sidecar's line come first. The supervisor spawns the
sidecar first, but spawning is not sequencing: without WaitForLeaderPort
nothing holds the engine back, so two shells race and the scheduler picks the
winner. It failed under full-suite load, and lately on its own.
The wait that is a real guarantee already has its own test, so the fix is to
check what this one is actually for — that both processes run under one shard,
that the shard's pid is the engine's rather than the sidecar's, and that their
output is distinguishable in a single log tail. Renamed to say so.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
