Unable to mock the native node:zlib module with TypeScript and Mocha/Chai/Sinon. about esmock

[SmashingQuasar]

@iambumblehead Hey!

Thanks for your super-quick answer!

Actually I figured out what I was doing wrong just before I read your answer. It was indeed because I was not using the returned mocked module and was attempting to use the native one. I probably misread the documentation, my bad!

It works perfectly using .mts and Sinon. Thanks for your work, this library works like a charm, it totally solved my issue!
It's unfortunate that the syntax is this heavy but I understand there is most likely no other way to do this as of today.

[iambumblehead]

@SmashingQuasar thanks for opening this issue. Two things, one: only the esmock-returned Response will use the mocked import tree and so that is the Response definition that should be used in the test,

-import { Response } from "../../../../src/main/Web/Server/Response.mjs";


-await esmock(
+const { Response } = await esmock(
	"../../../../src/main/Web/Server/Response.mts",
	import.meta.url,
	{
		zlib: {
			createGzip: {
				pipe: () =>
				{
					console.debug("pipe called 2");
				}
			}
		}
	}
);

The other thing is that esmock's scripted resolver might not handle the 'mts' extension correctly. If that's the case, run the test process with --experimental-import-meta-resolve to use node's native resolver. If --experimental-import-meta-resolve is needed, please open an issue here and I'll resolve the scripted resolver issue :)

esmock's own unit-tests are run twice for each test folder, one time with and another without --experimental-import-meta-resolve so example calls are seen there, for example this https://github.com/iambumblehead/esmock/blob/master/tests/tests-nodets/package.json#L17

esmock should work for your use-case