Vue Test Utils

Transitions

In general, you may want to test the resulting DOM after a transition, and this is why Vue Test Utils mocks <transition> and <transition-group> by default.

Following is a simple component that toggles a content wrapped in a fading transition:

<template>
  <button @click="show = !show">Toggle</button>

  <transition name="fade">
    <p v-if="show">hello</p>
  </transition>
</template>

<script>
import { ref } from 'vue'

export default {
  setup() {
    const show = ref(false)

    return {
      show
    }
  }
}
</script>

<style lang="css">
.fade-enter-active, .fade-leave-active {
  transition: opacity 0.5s ease;
}

.fade-enter-from, .fade-leave-to {
  opacity: 0;
}
</style>

Since Vue Test Utils stubs built-in transitions, you can test the component above as you'd test any other component:

import Component from './Component.vue'
import { mount } from '@vue/test-utils'

test('works with transitions', async () => {
  const wrapper = mount(Component)

  expect(wrapper.find('hello').exists()).toBe(false)

  await wrapper.find('button').trigger('click')

  // After clicking the button, the <p> element exists and is visible
  expect(wrapper.get('p').text()).toEqual('hello')
})