Bug: Using of plugins is impossible

[jimhucksly]

Describe the bug

To Reproduce
plugin.ts

import { App } from 'vue'

export default {
  install: (vue: App) => {
    const method = () => {
      ...
    }
    vue.config.globalProperties.$method = method
  }
}

component.vue

<template>
  <p>Vue Component</p>
</template>

test.spec.ts

import { mount, VueWrapper } from '@vue/test-utils'
import plugin from './plugin.js'
import component from './component.vue'

let wrapper: VueWrapper<Vue> = null
let component: Vue = null

async function setupTest() {
  wrapper = mount(component, {
    global: {
      plugins: [plugin]
    }
  })
  component = wrapper.vm
}

describe('App', () => {
  beforeEach(async () => {
    await setupTest()
  });

  it('router is ready', async () => {
    expect(component.$method).toBeDefined() // false
  })
})

**Expected behavior**
expect(component.$method).toBeDefined() // true

**Related information:**
  System:
    OS: Windows 10 10.0.19044
    CPU: (12) x64 Intel(R) Core(TM) i5-10600 CPU @ 3.30GHz
    Memory: 8.21 GB / 15.62 GB
  npmPackages:
    @vue/test-utils: ^2.3.1 => 2.3.1
    jest: ^26.6.3 => 26.6.3
    vue: ^3.2.20 => 3.2.20>

[freakzlike]

Hello @jimhucksly,

You are reassigning the variable component which is already set by the import statement. Can you try to use expect(wrapper.vm.$method).toBeDefined() instead and check if it's working?

[jimhucksly]

sorry, but the meaning of this does not change. i attach the correctly version of test.spec.ts

import { mount, VueWrapper } from '@vue/test-utils'
import plugin from './plugin.js'
import component from './component.vue'

let wrapper: VueWrapper<Vue> = null
let vm: Vue = null

async function setupTest() {
  wrapper = mount(component, {
    global: {
      plugins: [plugin]
    }
  })
  vm = wrapper.vm
}

describe('App', () => {
  beforeEach(async () => {
    await setupTest()
  });

  it('router is ready', async () => {
    expect(vm.$method).toBeDefined() // false
  })
})

[freakzlike]

Can you try to upgrade vue to the latest version?

It's working in the stackblitz example with the latest version: https://stackblitz.com/edit/vitest-dev-vitest-ynqmhz?file=test%2Fbasic.test.ts

[cexbrayat]

@jimhucksly This shouldn't really matter. Try to update Vue and Jest, as you're using quite old versions. If that's not enough, you can try to create a small repro in a Github repo and we'll take a closer look

[jimhucksly]

@cexbrayat Thank you, i have solved this problem.

[matthew-white]

@jimhucksly, I'm curious about how you solved the problem. After upgrading Vue and Vue Test Utils to the latest, properties set on config.globalProperties aren't accessible from the vm property of the VTU wrapper for me. It could be other issues with my setup (I'm still using Vue CLI, and I'm not using Jest), but it'd be very useful to hear what ended up working for you.