CF Bolz-Tereick16h ago
David R. MacIver

So like I mentioned I joined Antithesis a little while back. When I did, I pitched them on a crazy idea. Antithesis... Hypothesis... Hegel!

A remarkably short number of months later, Hegel. Hegel is a property-based testing protocol and family of client libraries which makes it easy to do Hypothesis-grade PBT everywhere.

Today: Rust. Tomorrow: The world! (Muahaha)

https://antithesis.com/blog/2026/hegel/

Hypothesis, Antithesis, synthesis

Introducing Hegel, our new family of property-based testing libraries.

Mar 24 at 3:20pmWeb
Show threadDavid R. MacIver1d ago

More soberly: In a week or two, Go. Then some other languages.

And of course a whole bunch of engineering and UX work as people use this thing and inevitably find that it is perfect and wonderful and has no flaws and we just have to spend all our time fielding praise for how great we are.

(And maybe fix a few bugs)

Show threadDavid R. MacIver1d ago
Lots of plans for the future of these libraries. This is very much just the start. But I'm pretty pleased with where we are as a start.
Show threadTin Tvrtković1d ago

@DRMacIver omg write another library

(just kidding, congrats and good luck!)

Show threadDavid R. MacIver1d ago

@tintvrtkovic What do you want from me! I wrote https://github.com/DRMacIver/shrinkray

It's a totally different testing tool that results from me obsessing about test-case reduction! I have breadth and versatility!

GitHub - DRMacIver/shrinkray: Shrinkray is a modern multi-format test-case reducer

Shrinkray is a modern multi-format test-case reducer - DRMacIver/shrinkray

GitHub
Show threadTin Tvrtković1d ago
@DRMacIver <3
Show threadwuest1d ago
@DRMacIver this rules so much. Amazing work as always!
Show threadtj usiyan1d ago
@DRMacIver Is there a way that I can help bring this to swift?
Show threadDavid R. MacIver1d ago

@griotspeak Today: It'll be a little bit rough, but you could try just porting the rust library. It's not a huge amount of code. Bet Claude or another coding agent could do most of the work.

We're going to get the protocol properly documented and to put a bunch more work into making it easy for people to spin up new libraries, but aren't quite there yet.

Show threadtj usiyan1d ago
@DRMacIver I was more interested in hand translating. Property tests have just the right amount of randomness already, in my view.
Show threadDavid R. MacIver1d ago
@griotspeak Yeah, hand translating also perfectly valid! Give it a go. It won't be entirely straightforward, but it should be a lot easier than a full Hypothesis port.
Show threadBadly-read literary snob1d ago
@griotspeak didn’t know you also write Swift! I’ve wanted such a library for a long while! I don’t wanna commit, as I’m already working on a side project, but if you give it a shot ping me! @DRMacIver
Show threadtj usiyan1d ago
@RosaCtrl @DRMacIver Yup! I currently use SwiftCheck but it is basically in maintenance mode since the main author now works at Apple. I *would* try to just pick up development myself but I don’t understand the e implementation well enough for all of that https://github.com/typelift/SwiftCheck
GitHub - typelift/SwiftCheck: QuickCheck for Swift

QuickCheck for Swift. Contribute to typelift/SwiftCheck development by creating an account on GitHub.

GitHub
Show threadCF Bolz-Tereick16h ago
@DRMacIver this is so cool! and, incidentally, for one of my current projects the C++ version of Hegel can't come soon enough...
Show threadPozorvlak15h ago
@DRMacIver hurrah!
Show threadAustin Bingham11h ago
@DRMacIver when you're ready to make Antithesis unusably slow we can integrate Cosmic Ray.