Bug: setProps not behaving as expected

[alextana92]

Describe the bug
setProps seems to work only in isolated tests, if more tests are present it doesn't seem to be updating the component props as expected

This started failing from 2.3.1

To Reproduce
https://codesandbox.io/p/devbox/eager-waterfall-57d5kh?file=%2Fsrc%2FApp.spec.js%3A19%2C6

When running npm run test you can see that the can change prop test fails, but if you only run that test with it.only("can change prop" it passes

this was not the case before 2.3.1, wonder if this is expected behaviour or not

also worth noting that if you remove the just an extra test the suite passes.

Related information:
This happens both on vitest and jest, the Vue version doesn't seem to matter either, I've seen these errors pop up in my codebase after upgrading vue test utils from 2.3.0 to 2.4.6

behaviour seems consistent with options/composition api

Additional context

[cexbrayat]

Hi @alextana92

It is indeed a weird behavior. In your repro, using mount instead of shallowMount appears to resolve the issue.

Is that the case for your real examples as well? In that case, that would mean that shallowMount had a regression.

If you can pinpoint the VTU version that introduced the regression, that might help chase the issue as well.

[alextana92]

Hi @alextana92

It is indeed a weird behavior. In your repro, using mount instead of shallowMount appears to resolve the issue.

Is that the case for your real examples as well? In that case, that would mean that shallowMount had a regression.

If you can pinpoint the VTU version that introduced the regression, that might help chase the issue as well.

hi @cexbrayat thanks for looking at it!

from what we've seen the errors start happening from version 2.3.1, the issue doesn't happen on 2.3.0

I have tried using mount in the real tests but I still get the errors, same behaviour as far as I can tell.
The only way I found to fix the issue was to move the mounting inside the it/test scope

as an example:

not working ❌

const wrapper = shallowMount(Mycomponent, {
     props: {
        ...propsData
     }
})

it('some test', () => {
     // assert something

     await wrapper.setProps({ some other props })

     // assert something else

     // set props does not work anymore if wrapper is outside `it/test` 
     // props don't get set
})

this seems to work fine ✅

it('some test', () => {
     const wrapper = shallowMount(Mycomponent, {
       props: {
          ...propsData
       }
     })
     // assert something

     await wrapper.setProps({ some other props })

     // assert something else

     // this works fine 
})

[cexbrayat]

Hmm strange. As we did not hear from users and v2.3.1 is quite old, I suppose this is not very common.

If you feel like it, you can try to fix it and open a PR, we would gladly appreciate it!

[alextana92]

Hmm strange. As we did not hear from users and v2.3.1 is quite old, I suppose this is not very common.

If you feel like it, you can try to fix it and open a PR, we would gladly appreciate it!

thank you @cexbrayat - I will look into it! Will join the discord in case I need some pointers 👍