npm install --save-dev karma-webpack
// Karma configuration
module.exports = function(config) {
config.set({
// ... normal karma configuration
files: [
// all files ending in "_test"
'test/*_test.js',
'test/**/*_test.js'
// each file acts as entry point for the webpack configuration
],
preprocessors: {
// add webpack as preprocessor
'test/*_test.js': ['webpack'],
'test/**/*_test.js': ['webpack']
},
webpack: {
// karma watches the test entry points
// (you don't need to specify the entry option)
// webpack watches dependencies
// webpack configuration
},
// optional middleware that blocks tests from running until code
// recompiles
beforeMiddleware: [
'webpackBlocker'
],
webpackMiddleware: {
// webpack-dev-middleware configuration
// i. e.
stats: 'errors-only'
},
plugins: [
require("karma-webpack")
]
});
};
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
'test/test_index.js'
],
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$/);
testsContext.keys().forEach(testsContext);
Every test file is required using the require.context and compiled with webpack into one test bundle.
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.
beforeMiddleware
is a webpack option that allows injecting middleware before
karama's own middleware are run. This loader provides a webpackBlocker
middleware that will block tests from running until code recompiles. That is,
given this scenario:
- Have a browser open on the karma debug page (http://localhost:9876/debug.html)
- Make a code change
- Refresh
Without the webpackBlocker
middleware karma will serve files from before
the code change. With the webpackBlocker
middleware the loader will not serve
the files until the code has finished recompiling.
Copyright 2014-2015 Tobias Koppers