for issue

vue-functional-component.spec.ts

import { FunctionalComponentOptions } from 'vue'
import { shallowMount, createLocalVue } from '@vue/test-utils'

let localVue: ReturnType<typeof createLocalVue>

describe('test', () => {
  beforeEach(() => {
    localVue = createLocalVue()
  })

  it('success mount', () => {
    const functionalComponent: FunctionalComponentOptions<{ tag: string }> = {
      functional: true,
      props: {
        tag: {
          type: String,
          default: 'div'
        }
      },
      render(h, { props: { tag } }) {
        return h(tag)
      }
    }
    const wrapper = shallowMount(functionalComponent, { localVue, propsData: { tag: 'p' } })
    expect(wrapper.html()).toMatchSnapshot();
  })
})