测试键盘、鼠标等其它 DOM 事件

触发事件

Wrapper 暴露了一个 trigger 方法。它可以用来触发 DOM 事件。

const wrapper = mount(MyButton)

wrapper.trigger('click')

你应该注意到了,find 方法也会返回一个 Wrapper。假设 MyComponent 包含一个按钮,下面的代码会点击这个按钮。

const wrapper = mount(MyComponent)

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

选项

trigger 方法接受一个可选的 options 对象。这个 options 对象里的属性会被添加到事件中。

注意其目标不能被添加到 options 对象中。

const wrapper = mount(MyButton)

wrapper.trigger('click', { button: 0 })

鼠标点击示例

待测试的组件

<template>
  <div>
    <button class="yes" @click="callYes">Yes</button>
    <button class="no" @click="callNo">No</button>
  </div>
</template>

<script>
  export default {
    name: 'YesNoComponent',

    props: {
      callMe: {
        type: Function
      }
    },

    methods: {
      callYes() {
        this.callMe('yes')
      },
      callNo() {
        this.callMe('no')
      }
    }
  }
</script>

测试

import YesNoComponent from '@/components/YesNoComponent'
import { mount } from '@vue/test-utils'
import sinon from 'sinon'

describe('Click event', () => {
  it('Click on yes button calls our method with argument "yes"', () => {
    const spy = sinon.spy()
    const wrapper = mount(YesNoComponent, {
      propsData: {
        callMe: spy
      }
    })
    wrapper.find('button.yes').trigger('click')

    spy.should.have.been.calledWith('yes')
  })
})

键盘示例

待测试的组件

这个组件允许使用不同的按键将数量递增/递减。

<template>
  <input type="text" @keydown.prevent="onKeydown" v-model="quantity" />
</template>

<script>
  const KEY_DOWN = 40
  const KEY_UP = 38
  const ESCAPE = 27

  export default {
    data() {
      return {
        quantity: 0
      }
    },

    methods: {
      increment() {
        this.quantity += 1
      },
      decrement() {
        this.quantity -= 1
      },
      clear() {
        this.quantity = 0
      },
      onKeydown(e) {
        if (e.keyCode === ESCAPE) {
          this.clear()
        }
        if (e.keyCode === KEY_DOWN) {
          this.decrement()
        }
        if (e.keyCode === KEY_UP) {
          this.increment()
        }
        if (e.key === 'a') {
          this.quantity = 13
        }
      }
    },

    watch: {
      quantity: function(newValue) {
        this.$emit('input', newValue)
      }
    }
  }
</script>

Test

import QuantityComponent from '@/components/QuantityComponent'
import { mount } from '@vue/test-utils'

describe('Key event tests', () => {
  it('Quantity is zero by default', () => {
    const wrapper = mount(QuantityComponent)
    expect(wrapper.vm.quantity).toBe(0)
  })

  it('Up arrow key increments quantity by 1', () => {
    const wrapper = mount(QuantityComponent)
    wrapper.trigger('keydown.up')
    expect(wrapper.vm.quantity).toBe(1)
  })

  it('Down arrow key decrements quantity by 1', () => {
    const wrapper = mount(QuantityComponent)
    wrapper.vm.quantity = 5
    wrapper.trigger('keydown.down')
    expect(wrapper.vm.quantity).toBe(4)
  })

  it('Escape sets quantity to 0', () => {
    const wrapper = mount(QuantityComponent)
    wrapper.vm.quantity = 5
    wrapper.trigger('keydown.esc')
    expect(wrapper.vm.quantity).toBe(0)
  })

  it('Magic character "a" sets quantity to 13', () => {
    const wrapper = mount(QuantityComponent)
    wrapper.trigger('keydown', {
      key: 'a'
    })
    expect(wrapper.vm.quantity).toBe(13)
  })
})

限制

点后面的按键名 keydown.up 会被翻译成一个 keyCode。这些被支持的按键名有:

key name key code
enter 13
esc 27
tab 9
space 32
delete 46
backspace 8
insert 45
up 38
down 40
left 37
right 39
end 35
home 36
pageup 33
pagedown 34

重要事项

Vue Test Utils 是同步触发事件。因此 Vue.nextTick 不是必须的。