karma-rollup-plugin

A Karma preprocessor plugin to offer seamless integration with rollup

This plugin is a Karma preprocessor to compile and bundle your spec entry point on the fly. It works seamless with all Rollup plugins.

Features

• supports Rollup by default
• supports both Babel and Buble as the ES2015 compiler
• sourceMap
• recompiling of dependencies when files changes
• ES3, ES5, ES2015, ES2016, and ES2017 (with Babel or Buble)

Installation

The easiest way is to keep karma-rollup-plugin as a devDependency. You can simple do it by:

npm i karma-rollup-plugin --save-dev

Configuration

Note! As a rule of thumb, use of umd format doesn't make sense in tests, and will throw a warning without a module name.

Following code shows the default configuration

// karma.conf.js
module.exports = function (config) {
  config.set({
    preprocessors: {
     'test/**/*.js': ['rollup']
    },
    rollupPreprocessor: {
      // rollup settings. See Rollup documentation
      plugins: [
        buble() // ES2015 compiler by the same author as Rollup
      ],
      // will help to prevent conflicts between different tests entries
      format: 'iife',
      sourceMap: 'inline'
    }
  });
};

See Rollup documentation - JavaScript API for more details.

Why this plugin?

There exist a karma-rollup-preprocessor plugin for Karma, but it contains too many bugs, and doesn't seem to be maintained atm. This plugin try to stay true to the Rollup ecosystem.