SFC Vue files with tests disappear from test coverage reports

[wopian]

I have Jest setup to test files with @vue/vue3-jest and it runs all of the Vue tests just fine, however I came across a peculiar issue regarding test coverage - it was going down in our CI dashboard as I was testing more components.

SFC Vue files without a *.spec.js test show up in the Jest coverage summary with zero coverage as expected. After adding a *.spec.js for a component, it will no longer collect or be listed in the coverage summary in our project.

Regular JavaScript files are unaffected and report coverage as expected.

I have a demo repository setup, however it only partially reproduces our issue - @components/Demo.vue is missing, but the two components in @components/demo/ show up fine (which doesn't happen in our project). Removing the @components/Demo.spec.js makes it show up again with zero coverage.

Demo: https://github.com/wopian/jest-coverage-demo

Demo moved to PR: #423

With Demo.spec.js, coverage unreported

With Demo.spec.js.old, (zero) coverage reported

vue: ^3.2.23
jest: ^27.3.1
@vue/vue3-jest: ^27.0.0-alpha.4

[lmiller1990]

Odd, definitely a bug. Is this something you might be interested in looking into? I'd recommend trying to reproduce it in this repo next, then we can easily debug, test and deploy a fix. You could add a test project here: https://github.com/vuejs/vue-jest/tree/master/e2e/3.x

[wopian]

I've added a more minimal reproduction project there, though I don't know if I will have the free time to investigate further due to work commitments

[lucassonsinlima]

Facing the same here, I'm trying to find out something that could cause this but I not went so far

vue: ^3.2.26
@vue/cli-plugin-unit-jest: ^5.0.0-rc.1
@vue/vue3-jest: ^27.0.0-alpha.4

[lmiller1990]

If anyone wants to take a look at this, it would be great! I'm too busy to look at vue-jest bugs at this point in time.

[jonsalvas]

for those who are interested: we had the same issue in our project and as workaround we returned to

"vue-jest": "^5.0.0-alpha.10",

for now until this issue is fixed.

[lmiller1990]

Interesting, we should find out the different between the code in v5 and @vue/vue3-jest@27 - they are very similar, it's just between the two, we moved from semantic versioning to matching the Jest version and a monorepo. The actual code is quite similar, so if someone can track down what broke and port it to @vue/vue3-jest@27, that'd be great.

[kinoli]

We had the same issue, switching the reporter to V8 fixed it.

[websmurf]

I'm not entirely certain if it's related, but we're seeing 'weird' things in coverage as well. (vue2 + vue-jest)
I've gone back in our pipeline and narrowed it down to this upgrade:

Difference in coverage:

[adholland]

Seeing exactly the same with recent version of (vue2 + vue-jest). Vue2 version 4.5.17, Vue-jest version 3.0.7.

[websmurf]

After my last comment, we've tried to reconstruct the coverage by downgrading. In the end, we also needed to downgrade @babel/core to version ^7.16.7 in order to make coverage working again.

So we are now in the situation that coverage is working again but with vue-jest@^3.0.7 and @babel/core@^7.16.7 on Jest 28.

[kinoli]

Why don't you just use V8?