The twitter replies are rather interesting. Regarding tests for "software engineering fitness", one simple test for abstract imagination would be very predictive: ask the candidate to imagine a 3x3 grid with digits, tell the digits row by row and ask to tell the sums column by column. The idea is to test the working memory of the candidate: if it only fits two digits, it won't be enough to make software. Extraordinary candidates would handle a 4x4 grid.