The best-effort-remove test provoked a real EACCES via a chmod-000 subtree,
which only fails for unprivileged users — under root, recursive rm ignores
permission bits, deleting the subtree: the existsSync assertion goes red and
the swallow branch loses coverage, failing the per-file gate. The rejection
is now injected deterministically at the node:fs/promises boundary (rm
wrapped with a real-passthrough vi.fn; one test queues a single rejection),
the fs-failure boundary being exactly the non-deterministic seam the testing
policy sanctions mocking. Everything else in the suite stays on the real
filesystem, and the swallow contract stays error-kind agnostic.
pku-xht
7ccf31a59b