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Comment by tyleo | Hacker News Reader

This is great. I learned several things reading this that I can immediately apply to my small personal projects.

1. Node has built in test support now: looks like I can drop jest!

2. Node has built in watch support now: looks like I can drop nodemon!

I tried node:test and I feel this is very useful for tiny projects and library authors who need to cut down on 3rd party dependencies, but it's just too barebones for larger apps and node:assert is a bit of a toy, so at a minimum you want to pull in a more full-fledged assertion library. vitest "just works", however, and paves over a lot of TypeScript config malarkey. Jest collapsed under its own weight.

As someone who eschewed jest and others for years for the simplicity of mocha, I still appreciate the design decision of mocha to keep the assertions library separate from the test harness. Which is to point out that chai [1] is still a great assertions library and only an assertions library.

(I haven't had much problem with TypeScript config in node:test projects, but partly because "type": "module" and using various versions of "erasableSyntaxOnly" and its strict-flag and linter predecessors, some of which were good ideas in ancient mocha testing, too.)

[1] https://www.chaijs.com/

Eh, the Node test stuff is pretty crappy, and the Node people aren't interested in improving it. Try it for a few weeks before diving headfirst into it, and you'll see what I mean (and then if you go to file about those issues, you'll see the Node team not care).

still I would rather use that than import mocha, chai, Sinon, istanbul.

At the end it's just tests, the syntax might be more verbose but Llms write it anyway ;-)

> but Llms write it anyway

The problem isn't in the writing, but the reading!

On a separate note, I’ve found that LLMs have been writing me really shitty tests. Which is really sad cause that was the first use case I had for copilot, and I was absolutely smitten.

They’re great at mocking to kingdom come for the sake of hitting 90% coverage. But past that it seems like they just test implementation enough to pass.

Like I’ve found that if the implementation is broken (even broken in hilariously obvious ways, like if (dontReturnPancake) return pancake; ), they’ll usually just write tests to pass the bad code instead of saying “hey I think you messed up on line 55…”

I just looked at the documentation and it seems there's some pretty robust mocking and even custom test reporters. Definitely sounds like a great addition. As you suggest, I'll temper my enthusiasm until I actually try it out.

Could you expand on the shortcomings of Node test compared to jest?

Module support is still experimental and under a flag and doesn't have any mechanism for mocking.

I still like jest, if only because I can use `jest-extended`.

If you haven't tried vitest I highly recommend giving it a go. It is compatible with `jest-extended` and most of the jest matcher libraries out there.

I've heard it recommended; other than speed, what does it have to offer? I'm not too worried about shaving off half-a-second off of my personal projects' 5-second test run :P

It has native TS and JSX support, excellent spy, module, and DOM mocking, benchmarking, works with vite configs, and parallelises tests to be really fast.

It also can transparently run tests directly in a browser rather than mocking the DOM, which is a very cool feature that I haven't used enough yet.

Jest is just not modern, it can't handle modern async/ESM/etc. out of the box. Everything just works in Vitest.

I don’t think it’s actually faster than Jest in every circumstance. The main selling point, IMO, is that Vitest uses Vite’s configuration and tooling to transform before running tests. This avoids having to do things like mapping module resolution behaviour to match your bundler. Not having to bother with ts-jest or babel-jest is also a plus.

Also it’s got a really nice browser UI. Colocates logs by specific test run. Super nice.

I’m sure there’s a package for jest to do that (idk maybe that’s what jest extended is?) but the vitest experience is really nice and complete

Last time I tried it, IDE integration (e.g. Test Explorer in VSCode) was lacking compared to Jest.

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