Cargo-nextest: 3x faster than cargo test, per-test isolation, first-class CI
nexte.st87 points by nateb2022 3 days ago
87 points by nateb2022 3 days ago
Thanks for posting about this! I'm the main author of nextest, and it represents my best foot forward for how Rust testing should be done. Happy to answer questions though I might be a bit intermittent.
Thank you very much for developing nextest. It is what allows our projects like rama [1] to run thousands and thousands of tests in a blink of an eye! Keep it up!
Big fan of nextest and this is my first time seeing this site. I'll be real I feel a bit ridiculous commenting this but you might want to consider rephrasing this:
>Treat tests as cattle, not pets. Detect and terminate slow tests.
Not sure saying, "hey, treat your tests as an animal you can kill at will" paints the right image.
This is from the Kubernetes saying of "treat servers like cattle, not pets". Of course, some people like me keep cattle as pets, but then again I also name my servers, even the virtual or containerised ones.
Yeah that was indeed the inspiration (though I'm pretty sure it predates Kubernetes!) but the juxtaposition with "terminate" is unfortunate.
That's fair! I'll find a way to rephrase it.
edit: Updated to "Detect and handle slow tests". Thanks again!
Have there been any discussions about upstreaming this into cargo proper? Are there any significant downsides to nextest compared to its predecessor?
The How it works [1] and Why process-per-test? [2] pages should answer your questions.
Ah, I see. You're aiming to become the hashbrown of testing.
Oh gosh, were we to be so lucky :) just aiming to solve problems my coworkers and users see, and doing it with care, is all.
The "execution model" page[1] is documentation at its best!
It answered 90% of the questions I had at the monent. Thank you!
seems like `cargo nextest run` just runs `--lib` tests by default? however, `cargo test` is not so slow if you do `cargo test --lib`. how do I get nextest to execute the doc tests, too?
I love nextest. without it my CI could take hours
https://github.com/tsz-org/tsz/actions/runs/29002057457/job/...
watch it running 32.5k unit tests without breaking a sweat!
Thanks! BTW you might enjoy setting CARGO_TERM_COLOR=always in your environment :) dtolnay/rust-toolchain does this automatically but it looks like you aren't using that action.
Thanks! Any pro tips for sharding? I landed on single job because couldn't get cache to work properly for shards to be fast enough to worth it
I love nextest, it's been great. This along with bacon catches a lot of issues.
Anybody using this in production?
edit: Thanks, will try!
Yes we use it for rama [1]. You can check its justfile and CI workflow file how we use it. Those run thousands and thousands of tests thx to nextest and what feels like instantly (once compiled).
Large projects build with rama use it as well. But those are proprietary from partners so sadly cannot share those.
Yes, for a long while – I believe it's fairly widely used (and it's absolutely excellent!)
Been using it for years, for opensource stuff and at work. No issues whatsoever.
I somehow tried to make sense of the name as a superlative form of "next". Perhaps next-test would have been fine?