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Falsify: Hypothesis-Inspired Shrinking for Haskell (2023)

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90 points birdculture | 1 comments | 20 Apr 25 19:41 UTC | HN request time: 0.209s | source
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mjw1007 ◴[20 Apr 25 22:51 UTC] No.43747119[source]▶
I've found in practice that shrinking to get the "smallest amount of detail" is often unhelpful.

Suppose I have a function which takes four string parameters, and I have a bug which means it crashes if the third is empty.

I'd rather see this in the failure report:

("ldiuhuh!skdfh", "nd#lkgjdflkgdfg", "", "dc9ofugdl ifugidlugfoidufog")

than this:

("", "", "", "")

replies(4): >>43747380 #>>43748889 #>>43749509 #>>43749569 #
1. yorwba ◴[21 Apr 25 08:19 UTC] No.43749509[source]▶
A minimal reproducing example cannot guarantee that you'll correctly diagnose a bug just by looking at the example (because multiple potential bugs could cause the same example to fail) but it can guarantee that when you step through the code to understand what's happening, you won't have to deal with huge amounts of irrelevant data.

Maybe an alternative shrinking procedure could directly minimize the number of instructions that need to be executed to hit a failure...