在All中引发错误-在使用Karma进行Web组件测试期间

Question

我有一个非常简单的Web组件，我想对其进行测试。我收到此问题主题中提到的错误。我发现了一个类似的问题Jasmine Karma Error "An error was thrown in afterAll\nUncaught ReferenceError: container is not defined thrown"，并且我已经检查出karma.conf.js中的路径和文件名是否存在错误。

还有什么可能导致提到的错误？

我的香草网络组件：

const templateString = `
    <div id="mydiv">
    </div>
`;
const template = document.createElement('template');
template.innerHTML = templateString;

export class SimplestWithoutBackend extends HTMLElement{
    constructor() {
        super();
        const shadowRoot = this.attachShadow({mode: 'open'});
        shadowRoot.appendChild(template.content.cloneNode(true));

    }
}
window.customElements.define("simplest-without-backend", SimplestWithoutBackend);

测试：

import { SimplestWithoutBackend } from './public/simplest-without-backend.js';

describe('simplest test', () => {
    let element, shadowRoot;
    beforeEach(() => {
        element = document.createElement('simplest-without-backend');
        shadowRoot = element.shadowRoot;
        document.body.append(element);
    });

    // check that the exposed API works
    describe('init', () => {
        it('should add a div under the shadow root', () => {
            expect(shadowRoot.querySelector('mydiv')).toBeTruthy();
        });
    });

});

package.json

{
  "name": "simplest-webcomponent",
  "version": "0.1.0",
  "private": true,
  "proxy": "http://localhost:5000",
  "dependencies": {
    "express": "^4.17.1",
    "jasmine": "^3.4.0",
    "mocha": "^6.1.4",
    "wct-browser-legacy": "^1.0.2",
    "web-component-tester": "^6.9.2"
  },
  "scripts": {
    "test": "karma start config/karma.conf.js"
  },
  "devDependencies": {
    "karma": "^4.1.0",
    "karma-jasmine": "^2.0.1"
  }
}

karma.conf.js

module.exports = function (config) {
    config.set({

        // base path that will be used to resolve all patterns (eg. files, exclude)
        basePath: '',

        client: {
            clearContext: false // leave Jasmine Spec Runner output visible in browser
        },
        // frameworks to use
        // available frameworks: https://npmjs.org/browse/keyword/karma-adapter
        frameworks: ['jasmine'],


        // list of files / patterns to load in the browser
        files: [
            '../test/simplest-without-backend-test.js'
        ],


        // list of files / patterns to exclude
        exclude: [],





        // test results reporter to use
        // possible values: 'dots', 'progress'
        // available reporters: https://npmjs.org/browse/keyword/karma-reporter
        reporters: ['progress'],


        // web server port
        port: 9876,


        // enable / disable colors in the output (reporters and logs)
        colors: true,


        // level of logging
        // possible values: config.LOG_DISABLE || config.LOG_ERROR || config.LOG_WARN || config.LOG_INFO || config.LOG_DEBUG
        logLevel: config.LOG_INFO,


        // enable / disable watching file and executing tests whenever any file changes
        autoWatch: true,


        // start these browsers
        // available browser launchers: https://npmjs.org/browse/keyword/karma-launcher
        browsers: ['Chrome'],


        // Continuous Integration mode
        // if true, Karma captures browsers, runs the tests and exits
        singleRun: false,

        // Concurrency level
        // how many browser should be started simultaneous
        concurrency: Infinity,

    })
};

cmd控制台：

# npm test

> simplest-webcomponent@0.1.0 test C:\_d\WSs\simplest-webcomponent
> karma start config/karma.conf.js

10 07 2019 18:08:37.038:WARN [karma]: No captured browser, open http://localhost:9876/
10 07 2019 18:08:37.175:INFO [karma-server]: Karma v4.1.0 server started at http://0.0.0.0:9876/
10 07 2019 18:08:37.176:INFO [launcher]: Launching browsers Chrome with concurrency unlimited
10 07 2019 18:08:37.185:INFO [launcher]: Starting browser Chrome
10 07 2019 18:08:39.756:INFO [Chrome 75.0.3770 (Windows 10.0.0)]: Connected on socket yjbpTPMBygpgPJK7AAAA with id 33592258
Chrome 75.0.3770 (Windows 10.0.0) ERROR
  An error was thrown in afterAll
  SyntaxError: Unexpected token {
Chrome 75.0.3770 (Windows 10.0.0): Executed 0 of 0 ERROR (0.029 secs / 0 secs)