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.
cogman10 2 minutes ago [-]
First, I like how all this works, it's great.
Can you run tests serially in the (horrible) case when tests need to build on one another?
How are you querying for the tests? Is that just built into rust's test stuff?
Would it be possible to fork the test process? It'd be pretty interesting if you could spawn a test process, and then fork it for each test to save both on memory and any static state stored within the test.
landr0id 8 hours ago [-]
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 8 hours ago [-]
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.
sunshowers 8 hours ago [-]
Yeah that was indeed the inspiration (though I'm pretty sure it predates Kubernetes!) but the juxtaposition with "terminate" is unfortunate.
wojciii 7 hours ago [-]
I liked the way it was phrased. You can't make everybody happy. :)
seanhunter 5 hours ago [-]
It’s a horrible saying in that context also.
embedding-shape 3 hours ago [-]
I mean, I like animals too, but in context it does make sense. The context was to treat them as "obtainable yet ultimately killable entities you keep as a group, not individuals", which cattle pretty much is. Unless you consider keeping cattle as draft animals, but I think that stopped being the main purpose a long time ago.
It got the point across, at a time where most people basically acquired servers, kept them until they died, and he was trying to push a development workflow where you constantly close("kill")/bring up new servers.
entrope 1 hours ago [-]
IMO, "make your servers fungible" is a better way to express the intent: slightly shorter, no metaphors, although "fungible" is a less common word. Maybe that's just me. (Edited to add: "make your tests fungible" has I think the wrong connotation; I think the original wording on the blog is about test executions -- and "make your test executions fungible" does seem like a good goal, similar to ACID guarantees for database transactions.)
embedding-shape 46 minutes ago [-]
Before that, I used to call them "ephemeral", and of course half the people asked what "ephemeral" means, probably "fungible" would be met with similar question, unless the crowd is cryptocurrency-adjacent, that term seems understood there.
jen20 1 hours ago [-]
That (unpleasant) saying predates Kubernetes by at least half a decade.
sunshowers 8 hours ago [-]
That's fair! I'll find a way to rephrase it.
edit: Updated to "Detect and handle slow tests". Thanks again!
mhluongo 2 hours ago [-]
It resonated with me!
Zababa 2 hours ago [-]
Fungible/non fungible is a good alternative, and maybe the technically correct word. But I think in that case it doesn't apply and the change the author did is better.
coding-wizard 2 hours ago [-]
Hey, I love nextest. But, perhaps because of the one-process per test approach, endpoint security solutions like CrowdStrike Falcon or Palo Alto Cortex tend to make computers hang whenever tests kick-in. I would love if you were able to introduce a workaround, because none of those companies will fix their stuff. I am guessing a possible mitigation would be to have stagger the first invocation of any large test binary, but I haven't had a chance to dig deep into this issue.
arw0n 1 hours ago [-]
Wouldn't running the tests in a container solve that issue? Or is that another thing that gets flagged?
gdcbe 6 hours ago [-]
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!
Super happy user here! It's an excellent piece of engineering.
We're running a fork that supports a "sidecar" server for running multiple integration tests against. So if any tests that need the server are included, it spawns the server, runs the integration tests, and then shuts it down. By re-using the same server we speed up our runs tremendously.
watch it running 32.5k unit tests without breaking a sweat!
sunshowers 6 hours ago [-]
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 5 hours ago [-]
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 5 hours ago [-]
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 somehow tried to make sense of the name as a superlative form of "next". Perhaps next-test would have been fine?
mightyham 4 hours ago [-]
Coming from the DC area, this comment reminds me of how the metro payment system "Smartrip" was recently renamed to "Smart Trip".
sunshowers 9 hours ago [-]
That is indeed the pun =)
patates 7 hours ago [-]
Oh, sorry then, thanks for the clarification :)
esafak 10 hours ago [-]
Anybody using this in production?
edit: Thanks, will try!
gdcbe 6 hours ago [-]
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.
Can you run tests serially in the (horrible) case when tests need to build on one another?
How are you querying for the tests? Is that just built into rust's test stuff?
Would it be possible to fork the test process? It'd be pretty interesting if you could spawn a test process, and then fork it for each test to save both on memory and any static state stored within the test.
>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.
It got the point across, at a time where most people basically acquired servers, kept them until they died, and he was trying to push a development workflow where you constantly close("kill")/bring up new servers.
edit: Updated to "Detect and handle slow tests". Thanks again!
[1] https://ramaproxy.org
[1] https://nexte.st/docs/design/how-it-works/
[2] https://nexte.st/docs/design/why-process-per-test/
It answered 90% of the questions I had at the monent. Thank you!
[1] https://nexte.st/docs/design/how-it-works/
We're running a fork that supports a "sidecar" server for running multiple integration tests against. So if any tests that need the server are included, it spawns the server, runs the integration tests, and then shuts it down. By re-using the same server we speed up our runs tremendously.
Discussion thread on gh: https://github.com/nextest-rs/nextest/discussions/3330
https://github.com/tsz-org/tsz/actions/runs/29002057457/job/...
watch it running 32.5k unit tests without breaking a sweat!
edit: Thanks, will try!
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