Maitz: local check of the fictional practice files (English version)
Check date: 2026-10-08
These files are an English translation of the October 3, 2026 kit: same rows, numbers, dates and formulas; text labels translated and the currency label set to USD.

PASS 12 source rows kept in the CSV
PASS 12 rows in the result, none deleted, original order
PASS IDs and leading zeros in the CSV
PASS source values identical in dirty-inventory-en.xlsx
PASS IDs stored as text in dirty-inventory-en.xlsx
PASS source values identical in clean-reference-en.xlsx
PASS IDs stored as text in clean-reference-en.xlsx
PASS leading zeros in the clean file
PASS IDs in the clean file remain text cells
PASS ambiguous dates not converted
PASS invalid date and missing date left without a normalized value
PASS valid dates stored as date cells
PASS zero quantity kept as zero, missing quantity left missing
PASS price in an unapproved format left missing
PASS 12 row-value formulas present, with type check and rounding
PASS independent sum: 64 known units
PASS 10 row values calculated, including the zero row
PASS independent partial sum only: 4,334.50 USD
PASS 34 change-log entries for value or type changes
PASS exact duplicate group detected from the source
PASS conflicting-ID group detected from the source
PASS no CSV cell starts with a risky formula character in the sample
PASS no macro or external link in dirty-inventory-en.xlsx
PASS no macro or external link in clean-reference-en.xlsx
PASS LibreOffice recalculation of the Validation sheet: 12 / 64 / 10 / 4,334.50 / 2
PASS temporary change of the first quantity from 10 to 11 updated the row value to 218.90 and the quantity sum to 65
PASS unchanged file (the change was made on a temporary copy) still gives 64 and 4,334.50
PASS dirty-inventory-en.xlsx: same structure, numbers and dates as the October 3 kit (only text translated)
PASS clean-reference-en.xlsx: same structure, numbers and dates as the October 3 kit (only text translated)
PASS source file signature unchanged: dirty-inventory-en.csv
PASS source file signature unchanged: dirty-inventory-en.xlsx

Partial values include duplicates. Do not use the total as a final business summary.
Limitation: no test was performed in the ChatGPT interface or in desktop Excel. Formulas were recalculated in LibreOffice Calc.
The checks cover this fictional practice kit only and are not a full security check for every CSV file.