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Cargo-nextest: 3x faster than cargo test, per-test isolation, first-class CI(nexte.st)
100 points by nateb2022 3 days ago | 29 comments
sunshowers 4 hours ago | parent | next [-]

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.

landr0id 4 hours ago | parent | next [-]

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.

trollbridge 4 hours ago | parent | next [-]

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.

seanhunter 35 minutes ago | parent | next [-]

It’s a horrible saying in that context also.

sunshowers 4 hours ago | parent | prev [-]

Yeah that was indeed the inspiration (though I'm pretty sure it predates Kubernetes!) but the juxtaposition with "terminate" is unfortunate.

wojciii 3 hours ago | parent [-]

I liked the way it was phrased. You can't make everybody happy. :)

sunshowers 4 hours ago | parent | prev [-]

That's fair! I'll find a way to rephrase it.

edit: Updated to "Detect and handle slow tests". Thanks again!

gdcbe 2 hours ago | parent | prev | next [-]

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!

[1] https://ramaproxy.org

mrec 2 hours ago | parent | prev [-]

Have there been any discussions about upstreaming this into cargo proper? Are there any significant downsides to nextest compared to its predecessor?

sunshowers 2 hours ago | parent [-]

The How it works [1] and Why process-per-test? [2] pages should answer your questions.

[1] https://nexte.st/docs/design/how-it-works/

[2] https://nexte.st/docs/design/why-process-per-test/

mrec 2 hours ago | parent [-]

Ah, I see. You're aiming to become the hashbrown of testing.

sunshowers 2 hours ago | parent [-]

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.

weinzierl 3 hours ago | parent | prev | next [-]

The "execution model" page[1] is documentation at its best!

It answered 90% of the questions I had at the monent. Thank you!

[1] https://nexte.st/docs/design/how-it-works/

satvikpendem 4 hours ago | parent | prev | next [-]

I love nextest, it's been great. This along with bacon catches a lot of issues.

mohsen1 2 hours ago | parent | prev | next [-]

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!

sunshowers 2 hours ago | parent [-]

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.

mohsen1 an hour ago | parent [-]

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

jstrong an hour ago | parent | prev | next [-]

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?

esafak 6 hours ago | parent | prev | next [-]

Anybody using this in production?

edit: Thanks, will try!

gdcbe 2 hours ago | parent | next [-]

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.

[1]: https://github.com/plabayo/rama

tekacs 6 hours ago | parent | prev | next [-]

Yes, for a long while – I believe it's fairly widely used (and it's absolutely excellent!)

musicmatze 2 hours ago | parent | prev | next [-]

Been using it for years, for opensource stuff and at work. No issues whatsoever.

aabhay 3 hours ago | parent | prev | next [-]

Yep. Tokio uses it for their tests in CI as well last I checked.

DennisL123 4 hours ago | parent | prev | next [-]

Yes, been using it for 18’ish months. Works great.

merqurio 5 hours ago | parent | prev [-]

Happy user here !

patates 5 hours ago | parent | prev [-]

I somehow tried to make sense of the name as a superlative form of "next". Perhaps next-test would have been fine?

mightyham 4 minutes ago | parent | next [-]

Coming from the DC area, this comment reminds me of how the metro payment system "Smartrip" was recently renamed to "Smart Trip".

sunshowers 4 hours ago | parent | prev [-]

That is indeed the pun =)

patates 3 hours ago | parent [-]

Oh, sorry then, thanks for the clarification :)