How does vue test utils jest work?

Question

Vue.js

I'm using prebuilt element.io components in a project and wanted to test the work done with vue test utils it's written in jest when I wrote the first test to try

import {
  mount
} from '@vue/test-utils'
import register from '@/components/form-reg.vue'

describe('Register', () => {
  const wrapper = mount(register)
  it('имеет кнопку', () => {
    expect(wrapper.contains('button')).toBe(true)
  })
})

gave me an error:

[Vue warn]: Unknown custom element: <el-row> - did you register the component correctly? For recursive components, make sure to provide the "name" option.

....
Who knows how to solve this problem?
Thanks for the answer!

Answer 1

Or import element-ui somewhere in setup.js (like this):

import Vue from "vue";
import ElementUI from 'element-ui';

Vue.use(ElementUI);

Or make stubs in the test:

import {mount} from '@vue/test-utils'
import register from '@/components/form-reg.vue'

describe('Register', () => {
  const wrapper = mount(register, {
    stubs: {
      'el-row': '<div></div>'
    }
  })
  it('имеет кнопку', () => {
    expect(wrapper.contains('button')).toBe(true)
  })
})

Answer 2

You need to call usebefore your tests. For example like this

import { createLocalVue, mount } from '@vue/test-utils'
import ElementUI from 'element-ui';

const localVue = createLocalVue()
localVue.use(ElementUI);

And then pass the instance to the test
const wrapper = mount(register, {localVue})
See the documentation