jest 27 + svelte-jester 2

[patrickleet]

just tried upgrading jest + svelte-jest with the new release

getting various errors with different configurations.

See linked github actions builds for specifics

[patrickleet]

in CI I get different errors, which is odd, here's a public repo with github actions: https://github.com/CloudNativeEntrepreneur/sveltekit-eventsourced-funnel/pull/10/checks?check_run_id=3256813646

[sebastianrothe]

This is an issue with node v16.6.0 jestjs/jest#11708

Please upgrade your node version.

[sebastianrothe]

in CI I get different errors, which is odd, here's a public repo with github actions: https://github.com/CloudNativeEntrepreneur/sveltekit-eventsourced-funnel/pull/10/checks?check_run_id=3256813646

The error is related to Jest thinking you don't use ESM. Have a look over here #59 (comment)

[patrickleet]

I looked at that comment, which links to a PR.

Tbh, I'm not really sure what I'm supposed to change still.

[sidharthv96]

@benmccann I'm getting the following error with 2.1.0

> jest src

● Validation Error:

  Module svelte-jester in the transform option was not found.
         <rootDir> is: /Users/sidv/dev/turgen/ds-frontend

  Configuration Documentation:
  https://jestjs.io/docs/configuration

Is there any extra configuration required?
My jest.config.json

{
  "testEnvironment": "jsdom",
  "transform": {
    "^.+\\.svelte$": [
      "svelte-jester",
      {
        "preprocess": true
      }
    ],
    "^.+\\.ts$": "ts-jest"
  },
  "moduleNameMapper": {
    "^\\$lib(.*)$": "<rootDir>/src/lib$1",
    "^\\$app(.*)$": [
      "<rootDir>/.svelte-kit/dev/runtime/app$1",
      "<rootDir>/.svelte-kit/build/runtime/app$1"
    ]
  },
  "moduleFileExtensions": [
    "js",
    "ts",
    "svelte"
  ],
  "setupFilesAfterEnv": [
    "./src/setupTests.ts"
  ],
  "globals": {
    "ts-jest": {
      "tsconfig": "tsconfig.spec.json"
    }
  }
}

[benmccann]

2.1.1 is out now which fixes an issue with the file paths in package.json. I'm not sure if it changes things for you or not. If it doesn't, it would help to have a project to reproduce the error

[patrickleet]

@benmccann

The error still occurs here with 2.1.1 https://github.com/CloudNativeEntrepreneur/sveltekit-eventsourced-funnel/pull/10/checks?check_run_id=3473288531

That repo is public and that PR is a reproduction.

[patrickleet]

Here's another branch configured differently - experimental-vm-modules, removed esbuild-jest (which makes import.meta.env work), and extensionsToTreatAsEsm set:

CloudNativeEntrepreneur/sveltekit-eventsourced-funnel#26

This way fails because of the import.meta.env stuff though without esbuild-jest handling it.

Maybe the logic they have in there could be put into svelte-jester?

[patrickleet]

Took it a bit further here: CloudNativeEntrepreneur/sveltekit-eventsourced-funnel#30 by using a babel plugin to handle the import.meta.env stuff, but now getting require not defined from using mocks, cause I guess mocks don't work with ESM?

[mszkb]

This should be resolved with #69

[patrickleet]

this is working, imo - the only thing that is not working well with jest is mocking ESM, but that's a jest issue, not this lib. Example set up here: https://github.com/CloudNativeEntrepreneur/sveltekit-eventsourced-funnel

[benmccann]

@patrickleet not sure if you saw, but basic experimental mocking support has been checked in for ESM now and will be released hopefully tomorrow, so perhaps that issue is solved now as well. jestjs/jest@90d6908

[patrickleet]

I did not - nice! I got creative without it for now haha. That will for sure come in handy for some more useful tests though.

[patrickleet]

@benmccann not sure if you saw, but the babel config I ended up with is pretty minimal - it ONLY handle import.meta.env stuff - could be useful for svelte-add jest config