karma-bro

karma-bro

Bro is a fast browserify integration for Karma that handles large projects with ease.

Installation

Get the plug-in via npm

npm install --save-dev karma-bro

Usage

Add browserify as a framework to your Karma configuration file. For each file that should be processed and bundled by karma, configure the browserify preprocessor. Optionally use the browserify config entry to configure how the bundle gets created.

module.exports = function(karma) {
  karma.set({

    frameworks: [ 'browserify', 'jasmine', 'or', 'any', 'other', 'framework' ],

    preprocessors: {
      'test/**/*.js': [ 'browserify' ]
    },

    browserify: {
      debug: true,
      transform: [ 'brfs' ]
    }
  });
}

Look at the example directory for a simple browserify + jasmine project that uses this plug-in.

Browserify Config

Test bundles can be configured through the browserify karma configuration property. Configuration options are passed directly to browserify.

For example to generate source maps for easier debugging, specify:

    browserify: {
      debug: true
    }

There are three properties that are not passed directly:

• transform
• plugin
• prebundle

Transforms

If you use CoffeeScript, JSX or other tools that need to transform the source file before bundling, specify a browserify transform (karma preprocessors are not supported).

    browserify: {
      transform: [ 'reactify', 'coffeeify', 'brfs' ]
      
      // don't forget to register the extensions
      extensions: ['.js', '.jsx', '.coffee']
    }

You can also specify options for the transformations:

    browserify: {
      transform: [ ['reactify', {'es6': true}], 'coffeeify', 'brfs' ]
    }

Plugins

The browserify plugin option supports the same syntax as transform.

    browserify: {
      plugin: [ 'stringify' ]
    }

Additional Bundle Configuration

You may perform additional configuration in a function that you pass as the prebundle option and that receives the bundle as an argument. This is useful when you need to set up things like externals:

    browserify: {
      prebundle: function(bundle) {
        bundle.external('foobar');
      }
    }

How it Works

Bro is a preprocessor for Karma that combines test files and dependencies into a browserified bundle. It relies on watchify to generate the bundle and to keep it updated during autoWatch=true.

Before the initial test run Bro builds one browserify bundle for all test cases and dependencies. Once any of the files change, it incrementally updates the bundle. Each file included in karma is required from the file bundle via a stub. Thereby it ensures tests are only executed once per test run.

Detailed Configuration

The following code snippet shows a Karma configuration file with all Bro related options.

module.exports = function(karma) {
  karma.set({

    // include browserify first in used frameworks
    frameworks: [ 'browserify', 'jasmine' ],

    // add all your files here,
    // including non-commonJS files you need to load before your test cases
    files: [
      'some-non-cjs-library.js',
      'test/**/*.js'
    ],

    // add preprocessor to the files that should be
    // processed via browserify
    preprocessors: {
      'test/**/*.js': [ 'browserify' ]
    },

    // see what is going on
    logLevel: 'LOG_DEBUG',

    // use autoWatch=true for quick and easy test re-execution once files change
    autoWatch: true,

    // add additional browserify configuration properties here
    // such as transform and/or debug=true to generate source maps
    browserify: {
      debug: true,
      transform: [ 'brfs' ],
      prebundle: function(bundle) {
        // additional configuration, e.g. externals
        bundle.external('foobar');
      }
    }
  });
};

Related

Credit goes to to karma-browserify and karma-browserifast. Bro builds on the lessons learned in these projects and offers improved configurability, speed and/or the ability to handle large projects.

Maintainers

• Ben Drucker
• Nico Rehwaldt

License

MIT