This synthetic fixture uses comma delimiters, a header row and double-quoted fields. Records end in CRLF; one quoted field contains an LF newline. Identifiers are strings.
Fields
id, item, quantity, unit_price, note. Prices are decimal test values, not live product prices. The literal note null is text; an empty quoted note is an empty string.
Checks to run
Count logical records separately from physical lines. Preserve identifier zeros and doubled quotes. If you calculate a total, multiply quantity by unit_price using decimal arithmetic. A parser that splits the file on newline before reading CSV will mishandle the multiline field.