Note that as recommended by John Regehr, author of C-Reduce, for this use case you might also want to try Shrinkray, a tool that was written to be format independent and works well for cases that C-Reduce dow not: https://mastodon.social/@regehr/113489759789563570
I accidentally got obsessed with test-case reduction as a result of writing Hypothesis, and wrote shrinkray because I thought it was ridiculous that I hadn't put all of the things I'd learned about test-case reduction into some general purpose tool that other people could benefit from.
Shrinkray is still a bit under-advertised and rough around the edges in places, but I think that basically there's no good reason to use C-reduce over shrinkray for things that aren't C or C++. Shrinkray has very good generic heuristics that should work in most languages (it even works pretty well on binary files apparently, although I've not tested this myself), a couple of language specific passes for other languages, and is much more fun to watch.
It might even be the case that you should use shrinkray for C and C++ too (because I use C-Reduce's transformations for those languages), but I'm less confident that that's true. The best I'll confidently claim is "probably more competitive than you'd expect".
Yes, hypothesis also does minimization of failed test cases, so it's kind of a similar problem, just a question if what format the data is in and how you invoke your test.
