/webpack 1

Usage With Karma




npm install --save-dev karma-webpack


// karma.conf.js  --  karma configuration

// if you import your existing 'webpack.config.js' setup here,
// be sure to read the note about 'entry' below.

module.exports = function(config) {
        // ... normal karma configuration

        files: [
            // all files ending in "_test"
            // each file acts as entry point for the webpack configuration

        preprocessors: {
            // add webpack as preprocessor
            'test/*_test.js': ['webpack'],
            'test/**/*_test.js': ['webpack']

        webpack: {
            // you don't need to specify the entry option because
            // karma watches the test entry points
            // webpack watches dependencies

            // ... remainder of webpack configuration (or import)

        webpackMiddleware: {
            // webpack-dev-middleware configuration
            // i.e.
            noInfo: true,
            // and use stats to turn off verbose output
            stats: {
                // options i.e. 
                chunks: false

        plugins: [


For additional information about webpackMiddleware.stats options see Stats Options

Alternative usage

This configuration is more performant, but you cannot run single test anymore (only the complete suite).

The above configuration generates a webpack bundle for each test. For many testcases this can result in many big files. The alterative configuration creates a single bundle with all testcases.

        files: [
            // only specify one entry point
            // and require all tests in there

        preprocessors: {
            // add webpack as preprocessor
            'test/test_index.js': ['webpack']
// test/test_index.js

// require all modules ending in "_test" from the
// current directory and all subdirectories
var testsContext = require.context(".", true, /_test$/);

Every test file is required using the require.context and compiled with webpack into one test bundle.

Source Maps

You can use the karma-sourcemap-loader to get the source maps generated for your test bundle.

npm install --save-dev karma-sourcemap-loader

And then add it to your preprocessors

preprocessors: {
    'test/test_index.js': ['webpack', 'sourcemap']

And tell webpack to generate sourcemaps

webpack: {
  // ...
    devtool: 'inline-source-map'


This is the full list of options you can specify in your Karma config.


Webpack configuration.


Configuration for webpack-dev-middleware.


Copyright 2014-2015 Tobias Koppers


© 2012–2015 Tobias Koppers
Licensed under the MIT License.