Vue unit test

the vue unit test is configured as follows, but the final result is shown in the figure. Why is there no component under test?
clipboard.png
specs

import Vue from "vue"
import HelloWorld from "../../../examples/components/HelloWorld.vue"

describe("HelloWorld.vue", () => {
  it("should render correct contents", () => {
    const Constructor = Vue.extend(HelloWorld)
    const vm = new Constructor().$mount()
    expect(vm.$el.querySelector(".hello h1").textContent)
      .to.equal("Welcome to Your Vue.js App")
  })
})

index.js

import Vue from "vue";

Vue.config.productionTip = false;

// require all test files (files that ends with .spec.js)
const testsContext = require.context("./specs", true, /\.spec$/);
testsContext.keys().forEach(testsContext);

// require all src files except main.js for coverage.
// you can also change this to match only the subset of files that
// you want coverage for.
const srcContext = require.context("../../examples", true, /^\.\/(?!main(\.js)?$)/);
let arr = srcContext.keys().filter(item => {
  return item !== "./index.html"
})

arr.forEach(srcContext);

karma.config.js

// This is a karma config file. For more details see
//   http://karma-runner.github.io/0.13/config/configuration-file.html
// we are also using it with karma-webpack
//   https://github.com/webpack/karma-webpack

var webpackConfig = require("../../build/webpack.test.conf");

module.exports = function (config) {
  config.set({
    // to run in additional browsers:
    // 1. install corresponding karma launcher
    //    http://karma-runner.github.io/0.13/config/browsers.html
    // 2. add it to the `browsers` array below.
    browsers: ["PhantomJS"],
    frameworks: ["mocha", "sinon-chai", "phantomjs-shim"],
    reporters: ["spec", "coverage"],
    files: ["./index.js"],
    preprocessors: {
      "./index.js": ["webpack", "sourcemap"]
    },
    webpack: webpackConfig,
    webpackMiddleware: {
      noInfo: true,
    },
    coverageReporter: {
      dir: "./coverage",
      reporters: [
        { type: "lcov", subdir: "." },
        { type: "text-summary" },
      ]
    },
  });
};
Mar.09,2021
MySQL Query : SELECT * FROM `codeshelper`.`v9_news` WHERE status=99 AND catid='6' ORDER BY rand() LIMIT 5
MySQL Error : Disk full (/tmp/#sql-temptable-64f5-1b3320e-2abb3.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
MySQL Errno : 1021
Message : Disk full (/tmp/#sql-temptable-64f5-1b3320e-2abb3.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
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