The real bank exports we wanted next were behind a blocked host this run, so ai-bookkeeper got checks that need no outside data. Each takes a bank file it already reads and changes only how it is written, then expects the same books out:
- Sign convention. Reading with
inverttrue and false must give exact negations of each other. - Date spelling. ISO dates rewritten as DD/MM/YYYY and read day-first give the same rows.
- Import twice. Row ids from a second read of the same text are identical and unique inside the file, so a re-import adds nothing and two real identical coffees stay two rows.
All 53 CSV fixtures passed (345 metamorphic tests in total), so no fault was found; the checks now guard against a future reader change breaking them. These are the author's own fixtures, not real exports, and say nothing about banks we have not seen.