unit-testing - karma 运行测试用例两倍

Question

我正在使用 karma 进行 angular 2 单元测试。它对我来说工作正常，但我有一件事我不知道为什么会发生。当我运行测试用例时使用 karma ，我测试的每个函数都会运行两次。当我在测试用例中使用的那个函数上打印 console.log 时，我知道这个问题。我不我不知道为什么会这样。请帮助我。

我将它与 webpack 一起使用。

webpack: bundle is now VALID.
17 10 2016 10:02:20.102:INFO [karma]: Karma v1.2.0 server started at http://localhost:9876/
17 10 2016 10:02:20.106:INFO [launcher]: Launching browser Chrome with unlimited concurrency
17 10 2016 10:02:20.188:INFO [launcher]: Starting browser Chrome
17 10 2016 10:02:40.019:INFO [Chrome 52.0.2743 (Linux 0.0.0)]: Connected on socket /#bNq05S_5S6il-eenAAAA with id 72225563
LOG: 'headers = {"content-type":["application/json"]}'
LOG: 'headers = {"content-type":["application/json"]}'
  Global Service : Login Authentication
    ✔ Should have operator login Authentication
LOG: 'headers = {"content-type":["application/json"],"authorization":["Token ad42hjk234bad8808"]}'
LOG: 'headers = {"content-type":["application/json"],"authorization":["Token ad42hjk234bad8808"]}'
LOG: 'catch 400 = {"_body":"{\"username\":\"xyz@gmail.com\",\"password\":\"761e768a501c30ea8e38\"}","status":400,"ok":false,"statusText":null,"headers":null,"type":null,"url":null}'
LOG: 'catch 400 = {"_body":"{\"username\":\"xyz@gmail.com\",\"password\":\"761e768a501c30ea8e38\"}","status":400,"ok":false,"statusText":null,"headers":null,"type":null,"url":null}'
    ✔ Should be call error page if login credential wrong
  Global Utils : Meta urls API
    ✔ Should have get Meta urls
LOG: 'page error'
LOG: 'page error'
    ✔ If get Empty Response of MetaUrls with status code 200
LOG: 'page error'
LOG: 'page error'
    ✔ If get Empty Response of MetaUrls with status code 400
LOG: 'page error'
LOG: 'page error'
    ✔ Should not have get Meta urls data with status code 404

Finished in 0.473 secs / 0.431 secs

SUMMARY:
✔ 6 tests completed

karma.conf.js

/**
 * @author: @AngularClass
 */

module.exports = function (config) {
  var testWebpackConfig = require('./config/webpack.test.js')({env: 'test'});

  var configuration = {

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

    /*
     * Frameworks to use
     *
     * available frameworks: https://npmjs.org/browse/keyword/karma-adapter
     */
    frameworks: ['jasmine'],

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

    /*
     * list of files / patterns to load in the browser
     *
     * we are building the test environment in ./spec-bundle.js
     */
    files: [
       { pattern: './config/spec-bundle.js', watched: false }
    ],

    /*
     * preprocess matching files before serving them to the browser
     * available preprocessors: https://npmjs.org/browse/keyword/karma-preprocessor
     */
    preprocessors: {
       './config/spec-bundle.js': ['coverage', 'webpack', 'sourcemap'],
    },

    // Webpack Config at ./webpack.test.js
    webpack: testWebpackConfig,

    coverageReporter: {
      type: 'in-memory'
    },

    remapCoverageReporter: {
      'text-summary': null,
      json: './coverage/coverage.json',
      html: './coverage/html'
    },


    // Webpack please don't spam the console when running in karma!
    webpackMiddleware: {stats: 'errors-only'},

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

    // 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: false,

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

    customLaunchers: {
      ChromeTravisCi: {
        base: 'Chrome',
        flags: ['--no-sandbox']
      }
    },

    plugin: [
      'karma-coverage',
      'karma-mocha-reporter',
      'karma-remap-coverage',
      'karma-sourcemap-loader',
      'istanbul-instrumenter-loader'
    ],

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

  if (process.env.TRAVIS) {
    configuration.browsers = [
      'ChromeTravisCi',
      'Chrome'
    ];
  }

  config.set(configuration);
};

spec-bundle.js

/**
 * @author: @AngularClass
 */

/*
 * When testing with webpack and ES6, we have to do some extra
 * things to get testing to work right. Because we are gonna write tests
 * in ES6 too, we have to compile those as well. That's handled in
 * karma.conf.js with the karma-webpack plugin. This is the entry
 * file for webpack test. Just like webpack will create a bundle.js
 * file for our client, when we run test, it will compile and bundle them
 * all here! Crazy huh. So we need to do some setup
 */
Error.stackTraceLimit = Infinity;

require('core-js/es6');
require('core-js/es7/reflect');

// Typescript emit helpers polyfill
require('ts-helpers');

require('zone.js/dist/zone');
require('zone.js/dist/long-stack-trace-zone');
require('zone.js/dist/proxy'); // since zone.js 0.6.15
require('zone.js/dist/sync-test');
require('zone.js/dist/jasmine-patch'); // put here since zone.js 0.6.14
require('zone.js/dist/async-test');
require('zone.js/dist/fake-async-test');

// RxJS
require('rxjs/Rx');

var testing = require('@angular/core/testing');
var browser = require('@angular/platform-browser-dynamic/testing');

testing.TestBed.initTestEnvironment(
  browser.BrowserDynamicTestingModule,
  browser.platformBrowserDynamicTesting()
);

/*
 * Ok, this is kinda crazy. We can use the context method on
 * require that webpack created in order to tell webpack
 * what files we actually want to require or import.
 * Below, context will be a function/object with file names as keys.
 * Using that regex we are saying look in ../src then find
 * any file that ends with spec.ts and get its path. By passing in true
 * we say do this recursively
 */
var testContext = require.context('../src', true, /\.spec\.ts/);

/*
 * get all the files, for each file, call the context function
 * that will require the file and load it up here. Context will
 * loop and require those spec files here
 */
function requireAll(requireContext) {
  return requireContext.keys().map(requireContext);
}

// requires and returns all modules that match
var modules = requireAll(testContext);

Answer 1

我遇到了同样的问题，这是因为“*.spec.js”文件需要可访问但不包含在内，所以你必须这样做:

files: [
       { pattern: './config/spec-bundle.js', watched: false },
       { pattern: '**/*.spec.js', included: false, served: true, watched: false }
    ]

这是我找到的来源:https://medium.com/@SchizoDuckie/so-your-karma-tests-run-twice-this-is-what-you-need-to-do-be74ce9f257e#.lqrkf24ty