The HR involved must be applying cargo cult rules of thumb without understanding the actual rules and the work the company does (which is, unfortunately, distressingly common for HR organizations.) If the actual work you did was such that a work sample would be indistinguishable from an IQ test (which it isn't, for almost any real work anywhere, and you'd have to be ignorant of either what the work is or what IQ tests are to make that mistake for most jobs) then IQ tests wouldn't be problematic in any case: IQ tests aren't specially prohibited in employment, they were just the immediate subject of one notable case which held that anything with a greater impact on a protected class is illegal if that impact is not warranted by the validity of the filter at issue as a measure of performance in the job for which it is used as a filter.