// 
<div class="hello">
    <son></son>
</div>

// HellWorld
import HelloWorld from "@/components/HelloWorld.vue"3
// vue-test-utils
import { mount, createLocalVue } from "vue-test-utils"
//  son
Vue.component("Son", require("@/components/son.vue"))

// .sonsondiv
console.log(wrapper.find(".son").text())

>  
> [vue-test-utils]: find did not return .son, cannot calltext() on empty Wrapper