vue-jest: Coverage report incorrect

Using yarn we were able to fix this by locking both versions of @babel/core and @babel/generator to 7.17.9 (thanks to the suggestion from @udebella )

"devDependencies": {
  "@babel/core": "7.17.9"
},
"resolutions": {
  "@babel/generator": "7.17.9"
},

We only use babel for jest so this doesn’t have any other side effects for us, YMMV.

"overrides": {
  "@babel/core": "7.17.9",
  "@babel/generator": "7.17.9",
  "istanbul-lib-instrument": "5.2.0"
}

works on vue3 too. thx @GrRivero @rklos

Why Im I seeing this error message TypeError: Cannot read properties of undefined (reading 'testEnvironmentOptions') It makes no sense, because I installed jest-environment-jsdom

This issue is not relevant to this topic at all !!!

This solved my issue https://github.com/vuejs/vue-jest/issues/522, probably worth trying here as well?

Upgrading couple of packages and editing jest.config.ts fixed the issue with coverage.

package.json

"@types/jest": "^29.2.2",
"jest": "^29.3.1",
"jest-environment-jsdom": "29.3.1",
"ts-jest": "^29.0.3",

jest.config.ts

moduleNameMapper: {
  uuid: require.resolve("uuid"),
},
coverageProvider: "v8",

Is there any other workaround? Downgrading @babel/core and @babel/generator didn’t work for me, the coverage is still incorrect. Downgrading jest and @vue/vue2-jest to versions 28 solves it partly, it generates valid coverage, but some files are missing for some reason…

EDIT: Installing jest@28 and @vue/vue2-jest@28 along with adding coverageProvider: v8 to jest config did the trick for me.

Using yarn we were able to fix this by locking both versions of @babel/core and @babel/generator to 7.17.9 (thanks to the suggestion from @udebella )

"devDependencies": {
  "@babel/core": "7.17.9"
},
"resolutions": {
  "@babel/generator": "7.17.9"
},

We only use babel for jest so this doesn’t have any other side effects for us, YMMV.

This fix has stopped working quite time ago. With step by step method I have found that the recent update of the istanbul-lib-instrument had broken something (there is an issue: https://github.com/istanbuljs/istanbuljs/issues/707).

So the next iteration of the workaround is (for npm >= 8):

"overrides": {
  "@babel/core": "7.17.9",
  "@babel/generator": "7.17.9",
  "istanbul-lib-instrument": "5.2.0"
}

@Envoy49 This topic talks about fixes for coverage reports. After following one of many fixes from this topic, the coverage reports issue was gone. I updgraded Jest from v27 to v28 || v29, and this error TypeError: Cannot read properties of undefined (reading 'testEnvironmentOptions') started. If it happened to me, it will surelly happen to other people. I had to rollback Jest to v27 because installing jest-environment-json did not fix the issue, as explained in jest’s official migration doc.

Why Im I seeing this error message TypeError: Cannot read properties of undefined (reading 'testEnvironmentOptions') It makes no sense, because I installed jest-environment-jsdom

update jest and @vue/vue2-jest to version 28.1.0 also did the trick for me

Any update on it?

Waiting for the fix, in the package.json:

• Add this into scripts section: “preinstall”: “npx npm-force-resolutions”
• Add this section to force babel generator version: “resolutions”: { “@babel/generator”: “7.17.9” }, On my side it worked and it will be fine while waiting for the version upgrade with the fixes

I’m also having this issue. Is the above PR being considered for a resolution here?

I’ve also been investigating this, in our case we do not use vite, but it seems to be related to babel 7 switching from source-map to @jridgewell/gen-mapping here: https://github.com/babel/babel/blob/main/CHANGELOG.md#v71710-2022-04-29

I have downgraded my @babel/core to 7.17.9 just before switched to @jridgewell/gen-mapping on 7.17.10 but it seems no luck

Anyone with a proposed solution much appreciated

Downgrading to 7.17.9 does not work because in @babel/core they did not freeze their dependencies. If you have a project that work, just make sure you don’t upgrade @babel/core dependencies: removing and recreating your package-lock.json leads to issue. 😦

My really ugly workaround is to to prevent @babel/generator to update to a buggy version. So I added inside my package.json:

  "overrides": {
    "@babel/generator": "<7.17.9"
  }

Then doing an npm install fixes broken package-lock.json. Be careful with this fix, because it forces a version of one dependency inside @babel/core which seems to rely on consistent versions : this workaround could not work or break your project: don’t forget to remove the override part from your package.json when this issue is fixed.

Maybe knowing where the issue comes from more precisely will help maintainers?

Edit: This solution works only for npm > 8.3.0 as overrides were introduced in this version. If you still use an older version, you can use @AnthonyRuelle solution If you use yarn, you can use @BenShelton solution

I’ve also been investigating this, in our case we do not use vite, but it seems to be related to babel 7 switching from source-map to @jridgewell/gen-mapping here:

https://github.com/babel/babel/blob/main/CHANGELOG.md#v71710-2022-04-29

I have downgraded my @babel/core to 7.17.9 just before switched to @jridgewell/gen-mapping on 7.17.10 but it seems no luck

Anyone with a proposed solution much appreciated