The first full scan logged "Invalid data found when processing input" per file and
carried on. That line is about the file: the scanner skips it, so the book never
appears in the library at all. Census of the 43 refused files: 38 were 0 bytes, 3
held WAV bytes behind a .mp3 name, 2 were unreadable. The check to run first is a
byte count, not a server investigation.
Full suite: 818 tests, exit 0.