karma-coverage

Generate code coverage using Istanbul.

Installation

The easiest way is to keep karma-coverage as a devDependency in your package.json.

{
  "devDependencies": {
    "karma": "~0.10",
    "karma-coverage": "~0.1"
  }
}

You can simple do it by:

npm install karma-coverage --save-dev

Configuration

Following code shows the default configuration...

// karma.conf.js
module.exports = function(config) {
  config.set({
    files: [
      'src/**/*.js',
      'test/**/*.js'
    ],

    // coverage reporter generates the coverage
    reporters: ['progress', 'coverage'],

    preprocessors: {
      // source files, that you wanna generate coverage for
      // do not include tests or libraries
      // (these files will be instrumented by Istanbul)
      'src/*.js': ['coverage']
    },

    // optionally, configure the reporter
    coverageReporter: {
      type : 'html',
      dir : 'coverage/'
    }
  });
};

Example use with a CoffeeScript project...

// karma.conf.js
module.exports = function(config) {
  config.set({
    files: [
      'src/**/*.coffee',
      'test/**/*.coffee'
    ],

    // coverage reporter generates the coverage
    reporters: ['progress', 'coverage'],

    preprocessors: {
      // source files, that you wanna generate coverage for
      // do not include tests or libraries
      // (these files will be instrumented by Istanbul via Ibrik unless
      // specified otherwise in coverageReporter.instrumenter)
      'src/*.coffee': ['coverage'],

      // note: project files will already be converted to
      // JavaScript via coverage preprocessor.
      // Thus, you'll have to limit the CoffeeScript preprocessor
      // to uncovered files.
      'test/**/*.coffee': ['coffee']
    },

    // optionally, configure the reporter
    coverageReporter: {
      type : 'html',
      dir : 'coverage/'
    }
  });
};

Options

type

Type: String

Possible Values:

• html (default)
• lcov (lcov and html)
• lcovonly
• text
• text-summary
• cobertura (xml format supported by Jenkins)
• teamcity (code coverage System Messages for TeamCity)

If you set type to text or text-summary, you may set the file option, like this.

coverageReporter: {
  type : 'text',
  dir : 'coverage/',
  file : 'coverage.txt'
}

If no filename is given, it will write the output to the console.

dir

Type: String

Description: This will be used to output coverage reports. When you set a relative path, the directory is resolved against the basePath.

subdir

Type: String

Description: This will be used in complement of the coverageReporter.dir option to generate the full output directory path. By default, the output directory is set to ./config.dir/BROWSER_NAME/, this option allows you to custom the second part. You can either pass a string or a function which will be called with the browser passed as the only argument.

coverageReporter: {
  dir: 'coverage',
  subdir: '.'
  // Would output the results into: .'/coverage/'
}

coverageReporter: {
  dir: 'coverage',
  subdir: 'report'
  // Would output the results into: .'/coverage/report/'
}

coverageReporter: {
  dir: 'coverage',
  subdir: function(browser) {
    // normalization process to keep a consistent browser name accross different
    // OS
    return browser.toLowerCase().split(/[ /-]/)[0];
  }
  // Would output the results into: './coverage/firefox/'
}

multiple reporters

You can use multiple reporters, by providing array of options.

coverageReporter: {
  reporters:[
    {type: 'html', dir:'coverage/'},
    {type: 'teamcity'},
    {type: 'text-summary'}
  ],
}

instrumenter

Karma-coverage infers the instrumenter regarding of the file extension. The .coffee files are by default covered using Ibrik (an Istanbul analog for CoffeeScript files). It is possible to override this behavior and point out an instrumenter for the files matching a specific pattern. To do so, you need to declare an object under with the keys representing the pattern to match, and the instrumenter to apply. The matching will be done using minimatch. If two patterns match, the last one will take the precedence.

coverageReporter: {
  instrumenter: {
    '**/*.coffee': 'istanbul' // Force the use of the Istanbul instrumenter to cover CoffeeScript files
  },
  // ...
}

For more information on Karma see the homepage.