karma start --grep some/pattern
npm install karma-webpack-grepEnables you to run karma start --grep some/partial/path to limit which files karma-webpack bundles. This can give a huge performance boost when booting up karma in development.
$ npm install --save-dev karma-webpack-grep
When using karma-webpack, you must provide webpack config to karma. Use this module to extend the plugins of your webpack config:
``js
// somewhere in your karma.conf.js
module.exports = function (config) {
webpackConfig.plugins = (webpackConfig.plugins || []).concat(
grep({
grep: config.grep,
// same baseDir as used in karma conf
baseDir: 'client',
// same string as used in require.ensure
// in your main test file
// see https://github.com/webpack/karma-webpack#alternative-usage
testContext: '..'
})
)
}
Read a more in depth explanation of this approach at https://medium.com/@kidkarolis/karma-webpack-grep-super-fast-tests-in-dev-b11130e2c2c6.