Trouble is you can't use /dev/null as a filesystem, even for testing. On a related note, though, I've considered the idea of creating a "minimally POSIX-compli

Trouble is you can't use /dev/null as a filesystem, even for testing. On a related note, though, I've considered the idea of creating a "minimally POSIX-compliant" filesystem that randomly reorders and delays I/O operations whenever standards permit it to do so, along with any other odd behavior I can find that remains within the letter of published standards (unusual path limitations, support for exactly two hard links per file, sparse files that require holes to be aligned on 4,099-byte boundaries in spite of the filesystem's reported 509-byte block size, etc., all properly reported by applicable APIs).