Document why `node:test` exists

[spencerwilson]

Affected URL(s)

https://nodejs.org/api/test.html

Description of the problem

Background

The core module node:test was proposed in #40954 and shipped at Experimental stability in 18.0.0 via #42325. Dozens of people expressed support for the idea via 👍 reactions and written comments. The sentiment of commenters toward the feature is overwhelmingly supportive.

Problem

TL;DR the questions asked in #40954 (comment) seem unanswered, reducing the likelihood that node:test becomes adopted.

It's unclear what problems the project aims to solve by including a test runner in core.

...or should I say—given the broad support shown by participants in #40954 —that they're unclear to me. 😕

• If it's relevant, my background: I'm primarily a maintainer of Node.js applications, ~5 years of experience doing so, and am not a maintainer of any OSS.
• I'm unsure how "should X go in core?" questions are usually settled, or if there are heuristics that exist in docs somewhere or in the heads of regular contributors. I went looking and found https://github.com/nodejs/node/blob/68fb0bf553e2af3e0b61733d29e1e9ba7f73d9b2/doc/contributing/pull-requests.md#accept-that-there-are-different-opinions-about-what-belongs-in-nodejs, which doesn't address the question so much as COC concerns at the periphery of the question. The couple “sufficient to put a thing in core” criteria it does identify aren’t met by a testing framework.

@bcomnes had a comment here - #40954 (comment) - that resonated very much with me: It distilled and synthesized a lot of rough ideas that commenters had submitted up to that point. IMO his comment effectively highlights the variety of goals that people might have for the module. It seems to me that the questions he raised remain unanswered.

cc @nodejs/test_runner (which I saw referenced in nodejs/TSC#1194 (comment) as a recently formed team)

meta note: My framing of this as a docs request might not be the best. If this is more suited as a Discussion or other type of issue, please let me know. Thanks.

[bcomnes]

Finger to the wind now that things settled, a few node maintainers wanted a tape like test runner built in for their own tests in the node repo (functionality beyond the built in assert module) and possibly adoption from the wider ecosystem (outside of the original npm test test runner that was intended as the standard test entry point when Issacs was working on node/npm). This isn't an official description, just what it looks like from outside looking in.

[spencerwilson]

a tape like test runner built in for their own tests in the node repo

Thanks. Ah, that actually does relate to something in pull-requests.md:

One general rule of thumb is that if Node.js itself needs it (due to historic or functional reasons), then it belongs in Node.js.

I'm now wondering if the commenters in the original feature request issue skew toward Node maintainers and away from non-maintainers. Maybe the value/purpose is more self-evident to that first population than it is to the second.

[RaisinTen]

cc @nodejs/test_runner

[ljharb]

I think that’s true. The ecosystem itself hasn’t come anywhere close to settling on one preferred test runner pattern, and node should be adding things only after the ecosystem has rough consensus about what it wants.