data() unreachable for components using Vuelidate

[SzNagyMisu]

Version

1.0.0-beta.18

Reproduction link

https://codesandbox.io/s/5lrvnoynx

Steps to reproduce

When upgrading from 1.0.0-beta.17 (up to 1.0.0-beta.20 I tried), all my components that use vuelidate are unable to reach data(). If I try and test if the initial values are correctly set, I get an error message.

What is expected?

the properties of vm.$options.data() should be available for testing

What is actually happening?

data() cannot be reached

[LinusBorg]

I'm trying to understand your reproduction, but I can't follow. The two tests that it contains seems to be meant to pass if said error is thrown, but they fail for some other error. Not good for a reproduction.

But I tried to investigate nonetheless.

• Vuelidate adds a mixin that relies on this in the data function to be a component instance.
• calling the data function on its own directly does not do that.
• calling it like this works: vm.$options.data.call(vm) or data.call(vm)

This is not related to vue-test-utils in any way. If you do the following in main.js you get the same error:

const main = new Vue({
  el: "#app",
  components: { App },
  template: '<App ref="app"/>'
});

console.log(main.$refs.app.$options.data())

...while the following works:

const main = new Vue({
  el: "#app",
  components: { App },
  template: '<App ref="app"/>'
});

console.log(main.$refs.app.$options.data.call(main.$refs.app))

[SzNagyMisu]

Thank you for having had a look on this issue.
Yes, I was pretty sure, it had to do mostly with vuelidate, the only thing intriguing me was that it does work if I use @vue/test-utils 1.0.0-beta.17 or below. Any idea what could have changed in test-utils, explaining this?

(BTW, I modified the reproduction to expect the test to work)

Thanks!