element-plus/packages/components/virtual-list/setup-mock.ts

import defineGetter from '@element-plus/test-utils/define-getter'

export default () => {
  const clientWidth = defineGetter(
    HTMLElement.prototype,
    'clientWidth',
    function () {
      return parseInt(this.style.width, 10) || 0
    },
    0
  )

  const clientHeight = defineGetter(
    HTMLElement.prototype,
    'clientHeight',
    function () {
      return parseInt(this.style.height, 10) || 0
    },
    0
  )

  const scrollHeight = defineGetter(
    HTMLElement.prototype,
    'scrollHeight',
    function () {
      return Number.MAX_SAFE_INTEGER
    },
    0
  )

  const scrollWidth = defineGetter(
    HTMLElement.prototype,
    'scrollWidth',
    function () {
      return Number.MAX_SAFE_INTEGER
    },
    0
  )

  // clean up function
  return () => {
    clientWidth()
    clientHeight()
    scrollHeight()
    scrollWidth()
  }
}