如何在 karma-webpack 中按块运行单元测试？答案

【问题标题】：How to run unit tests by chunks in karma-webpack?如何在 karma-webpack 中按块运行单元测试？
【发布时间】：2017-12-13 18:38:16
【问题描述】：

我们在项目中使用了以下技术：

angularjs+typescript+webpack+karma+phantomjs

我们在项目中有超过 1000 个单元测试在运行 bu karma-phantomjs-launcher 并且在 Windows 机器上出现幻像崩溃，但以下异常：

[phantomjs.launcher]: Fatal Windows exception, code 0xc0000005.

是否可以将测试拆分为多个块并一个接一个地运行它们？

【问题讨论】：

标签： webpack phantomjs karma-runner karma-webpack

【解决方案1】：

解决方法如下： custom-karma.js

const Server = require('karma').Server;
const filesFromJson = require('./karma.files.json');
const glob = require("glob");
const cfg = require('karma/lib/config');
const _ = require("lodash");
const path = require("path");
const minConfig = require('./karma.min.js');
const EventEmitter = require('events');
class ChunkEmitter extends EventEmitter {}
const chunkEmitter = new ChunkEmitter();

// register karma server and setup listener.
const registerKarmaServerAndSetListeners = (config, chunkNumber) => {
    const server = new Server(
        config,
        () => {
          console.log('test suite are done' + chunkNumber);
          // when first chunk of tests is done we have to call another chunk
          const nextChunk = ++chunkNumber;
          console.log('proceeding  ' + nextChunk);
          chunkEmitter.emit('chunk' + nextChunk);
        }
    );
    // listening for server starting event and starting server.
    chunkEmitter.on('chunk' + chunkNumber, ()=> {
        console.log('staring ' + chunkNumber);
        server.start();
    });
}
const readAllSpecsSplitIntoChunksEmitServer = () => {
    glob("src/**/*spec.ts", {}, (er, files) => {
        // spliting all specs into chunks. 
        const chunkedFiles = _.chunk(files, 50);
        chunkedFiles.forEach((chunk, index) => {
            let chunkedFiles = filesFromJson.coreFiles.concat(chunk);
            let karmaConfig = cfg.parseConfig(path.resolve('./karma.config.js'), {
                files: chunkedFiles
            });
            registerKarmaServerAndSetListeners(karmaConfig, index);
        });
        // starting tests from chunk0
        chunkEmitter.emit('chunk0');
    })
}

readAllSpecsSplitIntoChunksEmitServer();

为了运行它，只需运行以下命令：node custom-karma.js

【讨论】：