[Bug Report] Tests using components with v-menu break with: TypeError: Cannot read property 'dark' of undefined

[laliluna]

Versions and Environment

Vuetify: 1.2.3
Last working version: 1.1.15
Vue: 2.5.17
Browsers: Firefox 61.0
OS: Mac OS 10.13

Steps to reproduce

Run yarn unit:test

======================
Original thread: #4987

This happens when testing:

[Vue warn]: Error in config.errorHandler: "TypeError: Cannot read property 'dark' of undefined"
TypeError: Cannot read property 'dark' of undefined

This happens when you attempt to mount any vue component that uses v-select:

wrapper = mount(Invite, {store, localVue, propsData: props, attachToDocument: true});

The actual code in the component:

<v-select
id="role"
v-bind:items="this.roles"
v-model="form.data.role"
label="Select user role"

The error is thrown at v-menu component on line: 211 which contains the following:

props: {
provide: {
theme: { isDark: this.$vuetify.dark || this.dark }
}
}

Versions and Environment

Vuetify: 1.20 or 1.21
Vue: 2.5.17
Browsers: N/A
OS: MacOS
Previously worked in:

Vuetify: 1.15
Vue: 2.5.17
Steps to reproduce

Attempt to test any component containing v-select using vue-dev-tools using the above mentioned versions.

Expected Behavior

to not throw the exception

Actual Behavior

throws exception [Vue warn]: Error in config.errorHandler: "TypeError: Cannot read property 'dark' of undefined"

Reproduction Link

https://github.com/laliluna/vuetify-bug-demo

Other comments

The weired thing is that I tried to create a codesandbox demo first but appearently it works in this environment.
See: https://codesandbox.io/s/201063371r

[lzhoucs]

I run into the same issue today and the following workaround worked for me:

// use
Vue.use(Vuetify)
// rather than
// localVue.use(Vuetify)

I was inspired by #4068 (comment) although the issue there seems not directly related to this one.

[umbertooo]

I experienced the same behaviour with Vuetify version 1.2.4 and solved it the same way as @lzhoucs posted above. But even with this workaround the test happens to log a lot [Vue warn]:... warnings. These logs could be suppressed using this snippet:
#3456 (comment)

While these workarounds may be acceptable temporarily I'd expect to use the Vuetify like every other Vue.js plugin with the Vue Test Utils (https://vue-test-utils.vuejs.org/guides/common-tips.html#applying-global-plugins-and-mixins) meaning using localVue.use(Vuetify) instead of Vue.use(Vuetify).

[ascott18]

Any updates on this? Would be great to be able to do localVue.use(Vuetify) since it is the officially prescribed method for testing Vue components.

[KaelWD]

See #4068 and vuejs/vue#8278, it's a problem with vue that was uncovered when we switched to typescript. There's nothing wrong with not using localVue, that's how it worked with avoriaz before vue-test-utils was a thing.