Not working with Jest

[KSXGitHub]

pnpm version:

1.30.2

Code to reproduce the issue:

Step 1: Use pnpm

• Clone this repo
• Run pnpm install
• Run pnpx jest

Step 2: Use yarn

• Delete node_modules
• Run yarn
• Run yarn jest

Expected behavior:

Step 1 doesn't fail

Actual behavior:

Step 1 fails while Step 2 doesn't

TypeError: environment.setup is not a function

My speculation:

Flat node_modules doesn't fail.

Additional question:

How to force pnpm create flat node_modules?

Additional information:

• node -v prints: v9.4.0
• Windows, OS X, or Linux?: Arch Linux

Related issue: jestjs/jest#5369

[nickpape]

When working on our project, we noticed that jest had a couple problems correctly resolving symlinked paths. First, we had to upgrade Jest to ~21.2.1, where they weren't missing dependencies in their package.json. Then, I noticed an issue with jest-resolve not properly resolving symlinks, so I created a PR for them, but don't yet have a CLA to fix the issue. We ended up doing a patch in our tools instead. You might be experiencing similar issues. First, I would definitely advice upgrading Jest, if possible.

jestjs/jest#5085
microsoft/rushstack#466

[KSXGitHub]

I just discovered a workaround for this yesterday: Replace jest with jest-cli. It worked.

This is the repo that I worked on.

[KSXGitHub]

I just discovered that the jest will fail if --preserve-symlinks flag is provided

Create a jest.js:

require('jest-cli/bin/jest')

✓ If I execute node jest.js, it works.

✕ If I execute node --preserve-symlink jest.js, it doesn't work.

✕ If I execute pnpm test with node jest.js being test script, it doesn't work. (No idea why)

✕ If I execute pnpx jest, it doesn't throw an irrelevant error message if I add a test to fail (e.g. expect(0).toBe(1)), but it passes if all tests pass.

[zkochan]

A node_modules created by pnpm won't work with Node ran with --preserve-symlinks (https://github.com/pnpm/pnpm#limitations). It is a limitation of pnpm because we use symlinks. Though this flag will most probably be deprecated

[KSXGitHub]

@zkochan I have no intention of using --preserve-symlinks either, the point that I wanna make here is that pnpm test and pnpx test still fails while node jest.js works.

[dandv]

Jest doesn't work for me either, but the error is SyntaxError: Unexpected token import on the line that imports my module (import { MyModule } from '..'). If I run npm install; npm run test instead of pnpm install; pnpm run test, Jest works. I'm using the latest Jest, 22.3.0.

@KSXGitHub's workaround didn't work (same error). My .babelrc is { "plugins": ["transform-es2015-modules-commonjs"] } because Jest doesn't support native ES6 modules.

[wmertens]

for me the error is Cannot find module 'jest-environment-jsdom' - v22.4.3.

The module is installed as part of the jest-cli deps, but not found by jest, presumably because it does weird things with require.

[wmertens]

It does work when doing --shamefully-flatten, which is good news I suppose, but of course Jest should be fixed to work with hierarchical modules.

[wmertens]

Jest works now, v23.6.0

[zkochan]

Cool!

[KSXGitHub]

@wmertens It works even without --shamefully-flatten?

[wmertens]

@KSXGitHub Yes! And if you want to use Babel 7 you need to override the dependencies as I explain in #1475

[mudlabs]

@wmertens I still get error with v23.6.0

Cannot find module 'jest-environment-jsdom'
at node_modules/.registry.npmjs.org/jest-runner/23.6.0/node_modules/jest-runner/build/run_test.js:39:29