3f53c221c8
The chunk-size-zero regression test spawned fcry with stdin piped and unconditionally unwrapped the write into that pipe. That made the test depend on scheduler timing: the child may validate --chunk-size 0, report the error, and exit before it has drained stdin. Treat BrokenPipe as the expected early-exit shape for this failing command, while still failing on any other write error and still asserting that the process exits unsuccessfully. The valid empty-stdin chunk-size case remains unchanged. Test Plan: - cargo fmt --check - cargo test - cargo clippy --all-targets -- -D warnings - git diff --check Refs: none