Hacker News: sunshowers

New comment by sunshowers in "Cargo-nextest: 3x faster than cargo test, per-test isolation, first-class CI"

sunshowers — Fri, 10 Jul 2026 23:13:25 +0000

Like all things in life, there is a balance :) I didn't remove the cattle vs pets analogy but I did replace "terminate" with "handle".

New comment by sunshowers in "EU Parliament greenlights Chat Control 1.0"

sunshowers — Thu, 09 Jul 2026 18:27:47 +0000

Look, you can either let people make a living and manage their own lives while contributing to society, or you can not let them make a living and ensure they're housed and fed. You can't be angry at A and also be angry at B.

New comment by sunshowers in "Cargo-nextest: 3x faster than cargo test, per-test isolation, first-class CI"

sunshowers — Thu, 09 Jul 2026 16:15:14 +0000

Nextest does run tests in lexicographic (binary, test name) order by default, so first executions tend to be staggered. Unfortunately this is a known problem that is much larger than nextest, and it is why Windows introduced Dev Drive with a mode to disable AV/EDR on those drives entirely.

I wish I had a better answer here — it is frustrating how poorly behaved the EDR stuff tends to be. Maybe I should try and network a bit to get in touch with the people working on this stuff. (Planning to be at DEF CON this year, so come find me if you work on this stuff and will be there!)

New comment by sunshowers in "EU Parliament greenlights Chat Control 1.0"

sunshowers — Thu, 09 Jul 2026 16:09:44 +0000

From what I can tell, a big part of the problem in Europe is that people seeking asylum are prohibited from making a living (due to widespread belief in the lump of labor fallacy) and so have to be dependent on welfare.

New comment by sunshowers in "Cargo-nextest: 3x faster than cargo test, per-test isolation, first-class CI"

sunshowers — Thu, 09 Jul 2026 15:04:24 +0000

The benchmarks are against non-doctest cargo test runs. (But you should measure against your own project, of course!) Unfortunately Cargo doesn't provide enough information for nextest to run doctests reliably with.

New comment by sunshowers in "Cargo-nextest: 3x faster than cargo test, per-test isolation, first-class CI"

sunshowers — Thu, 09 Jul 2026 15:02:10 +0000

I think in practice you're right that GitHub Actions' caching slowness can end up dominating performance. I don't have any great tips other than to measure.

New comment by sunshowers in "Cargo-nextest: 3x faster than cargo test, per-test isolation, first-class CI"

sunshowers — Thu, 09 Jul 2026 14:58:29 +0000

> Can you run tests serially in the (horrible) case when tests need to build on one another?

Yes: https://nexte.st/docs/configuration/test-groups/ (edit: though tests that build on each other is a bit harder — test groups are meant for when tests need access to a shared resource)

> How are you querying for the tests? Is that just built into rust's test stuff?

Just running --list against test binaries.

> 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.

This is possible in principle, but nextest doesn't really inject itself into tests like that (injection can cause reliability issues in practice, and a big focus of nextest is reliability). Forking is also not possible in multithreaded programs.

New comment by sunshowers in "Cargo-nextest: 3x faster than cargo test, per-test isolation, first-class CI"

sunshowers — Thu, 09 Jul 2026 08:32:46 +0000

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.

New comment by sunshowers in "Cargo-nextest: 3x faster than cargo test, per-test isolation, first-class CI"

sunshowers — Thu, 09 Jul 2026 07:57:31 +0000

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.

New comment by sunshowers in "Cargo-nextest: 3x faster than cargo test, per-test isolation, first-class CI"

sunshowers — Thu, 09 Jul 2026 07:50:15 +0000

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/

New comment by sunshowers in "Cargo-nextest: 3x faster than cargo test, per-test isolation, first-class CI"

sunshowers — Thu, 09 Jul 2026 06:33:36 +0000

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

New comment by sunshowers in "Cargo-nextest: 3x faster than cargo test, per-test isolation, first-class CI"

sunshowers — Thu, 09 Jul 2026 06:29:12 +0000

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

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

New comment by sunshowers in "Cargo-nextest: 3x faster than cargo test, per-test isolation, first-class CI"

sunshowers — Thu, 09 Jul 2026 05:50:08 +0000

That is indeed the pun =)

New comment by sunshowers in "Cargo-nextest: 3x faster than cargo test, per-test isolation, first-class CI"

sunshowers — Thu, 09 Jul 2026 05:48:57 +0000

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.

New comment by sunshowers in "Oxide computer 3D rack guided tour"

sunshowers — Thu, 25 Jun 2026 21:12:58 +0000

I'm sure you're aware there's a huge amount of computation that isn't matrix multiplication :)

New comment by sunshowers in "Oxide computer 3D rack guided tour"

sunshowers — Thu, 25 Jun 2026 21:11:49 +0000

My successful application took around 12 hours of writing and editing across 3 days, though I was lucky that most of my portfolio was already open source or otherwise public. Some people spend more, some spend less.

It is worth keeping in mind that we write a _lot_. If you don't enjoy the process of writing, you might not like working here.

New comment by sunshowers in "Formal methods and the future of programming"

sunshowers — Wed, 17 Jun 2026 02:33:22 +0000

We have a number of TLA+ models at Oxide. Here's one:

https://github.com/oxidecomputer/omicron/blob/8b0886dbd02229...

New comment by sunshowers in "How memory safety CVEs differ between Rust and C/C++"

sunshowers — Tue, 16 Jun 2026 19:40:25 +0000

Updated https://oxide.computer/blog/iddqd-unsafe#what-about-formal-m... with some notes.

New comment by sunshowers in "How memory safety CVEs differ between Rust and C/C++"

sunshowers — Mon, 15 Jun 2026 20:16:47 +0000

Mostly chatted with some people and figured it out with their help.

New comment by sunshowers in "How memory safety CVEs differ between Rust and C/C++"

sunshowers — Mon, 15 Jun 2026 19:22:30 +0000

Rust is a beautiful language. Gorgeous.