In Hit ‘em High, Hit ‘em Low: Regression Testing and the Saff Squeeze Kent Beck outlines a very nice technique for isolating a defect using regression tests:
“To effectively isolate a defect, start with a system-level test and progressively inline and prune until you have the smallest possible test that demonstrates the defect.”
Kent provides a step-by-step example of the technique, which he attributes to David Saff. I’ve always done the “High” part of the process, but the successive inlining and pruning to get to the “Low” is new and very clever. Tucked into my bag of tricks now.
(Link via PierG.)
Posted in: tdd
January 18th, 2009 → 8:03 pm
[...] thing that happened was that during one of those interminable 15-second waits I read about the Saff squeeze. Then I tried it, enjoyed it, and found that the tests it produced were significantly different [...]
January 18th, 2012 → 10:36 pm
[...] their efforts, and briefly looked at the code, but immideiately thought back to my days spent with Agile Coach Kevin Rutherford. Kevin used to tut disapprovingly every time we started the debugger, suggesting that we were just [...]