Doesn't work within jest

[timsuchanek]

When running an undici client in jest, jest is doing some kind of override magic in the background, that makes this check for a buffer in undici fail.

Reproduction: https://github.com/timsuchanek/undici-buffer-repro

I'm already working on a fix :) I suggest adding a || Buffer.isBuffer(body) in https://github.com/mcollina/undici/blob/master/lib/client.js#L946

[ronag]

I'm very curious what happens here. It shouldn't be possible for anyone to modify the Request object. Are they overriding Buffer.from or something?

[mcollina]

I would highly recommend to not use jest as it provides different globals for each test, making all those check fail.
Anyway, a fix would be welcomed. Please also add a test for it.

[timsuchanek]

@mcollina I guess you recommend using tap instead? We have all our tests written in jest, but it has its limits.

We once hit a similar problem in Prisma Client, where we had an instanceof Date check. As a naive library author I thought that's sufficient - but there is some test environment, I think it was https://quokkajs.com/ that overrides the global Date, therefore the instanceof doesn't work anymore.
So we had to move to a Object.prototype.toString test instead.

[timsuchanek]

It's kinda awkward to add jest in there, but this is the only sane way I found to add the test #319

[SimenB]

Sorry about Jest causing issues 🙁 The issue to track (if anybody wants) in Jest for this is jestjs/jest#2549. I've tried multiple times to fix it without luck. I believe it can be solved if these two are ever solved:

• Contexts created with vm.createContext() do not define the URL() constructor node#28823
• Evaluate node core modules within a vm.Context node#31852