Announcing HypoFuzz: a smart fuzzing backend for Hypothesis

[Zac Hatfield-Dodds]

Hey, Hypothesis Users!

I'm very excited to annouce the launch of HypoFuzz - a smart fuzzing tool for test suites using Hypothesis.  Existing fuzzers are great for testing one function at a time; HypoFuzz extends that to dynamically scheduling all of your tests to discover bugs as fast as possible, and with a minimum of configuration.

I was inspired by a wide range of fuzzing research, and a few notable tools like AFL, along with the workflow that Nelson Elhage wrote about in [1].  So if you want to complement your local and CI test runs with an ongoing search for "interesting" new inputs, check it out!  Failing inputs are reported in the dashboard, of course, but I usually just share the database - and so running the test locally is sufficient to reproduce any failures.

It's early days, so your feedback is really important - even or especially if you wouldn't use it!

• Check out https://hypofuzz.com/
• Email z...@hypofuzz.com to tell me what you wish it did differently, ask questions, describe your dream workflow, etc.
  I'm also happy to chat over video about any of this!
• Please forward this announcement to anyone you know who uses Hypothesis as part of a team.  Full-time teams are under-represented in open source and blogging, and I'd love to talk to them!

Finally, you may have noticed that HypoFuzz is not open-source.  I've been looking for a way to make working on Hypothesis sustainable for a while, and this seems like a good one: fuzzing is particularly valuable to professionals and teams with budgets but not so much to hobbyists and students, while the core tools of property-based testing and extensions like the Ghostwriter are equally valuable for everyone (and thus open-source).

So check it out, forward it on, wish me luck - and tell me what you think!

Best,

Zac Hatfield-Dodds

Core developer, Hypothesis; Founder, https://hypofuzz.com/

[1] https://blog.nelhage.com/post/property-testing-like-afl/