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Code Coverage shows how much of your code is covered with tests and marks covered and uncovered lines visually right in the editor.

In this section:

Prerequisites

  1. The JSTestDriver or Karma test runner is installed and configured.
  2. Additional third-party testing frameworks, for example, Jasmine, QUnit, or Mocha, are downloaded and integrated with IntelliJ IDEA.
  3. A runner-specific configuration file is generated or written manually.

For more details, see Preparing to Use Karma Test Runner or Preparing to Use JSTestDriver Test Runner depending on your choice.

Enabling running tests with coverage in Karma

Coverage for tests run in Karma is calculated by the istanbul coverage tool. The tool is shipped within the karma-coverage package. Therefore running tests with coverage in Karma requires that you download the karma-coverage package and manually update the karma.conf.js configuration file.

The karma-coverage package should be installed in the same folder with Karma (karma (library home) package), no matter whether Karma is installed globally or in your project. Keep this restriction in mind when installing karma-coverage manually in the command line mode. If you are installing karma-coverage through the Node Package Manager interface, the proper installation folder will be chosen automatically.

  1. Install the karma-coverage package through the Node Package Manager (npm).
    1. Open the Settings / Preferences Dialog by choosing File | Settings for Windows and Linux or IntelliJ IDEA | Preferences for OS X, and click Node.js and NPM under Languages&Frameworks.
    2. On the Node.Js and NPM page that opens, click Install in the Packages area.
    3. In the Available Packages dialog box that opens, select the karma-coverage package, click Install Package, and close the dialog box when ready. IntelliJ IDEA returns to the Node.js page, where the karma-coverage package is added to the Packages list. Click OK.

    For details, see Installing and Removing External Software Using Node Package Manager.

  2. Open the karma.conf.js configuration file and add the following information to it manually:
    1. Locate the reporters definition and add coverage to the list of values in the following format: 
      reporters: ['progress', 'coverage'],
    2. Add a preprocessors definition and specify the coverage scope according to the following format: 
      preprocessors: {
    '**/*.js': ['coverage']
}
Measuring code coverage for tests executed on JSTestDriver
  1. Prepare tests manually or have tests generated by IntelliJ IDEA.
  2. Create a JSTestDriver configuration file *.jstd or *.conf. For details, see JSTestDriver Configuration file.
  3. Create a run configuration of the type JSTestDriver.

    To have specific files excluded from coverage analysis, specify the paths to them in the Coverage tab of the Run/Debug Configuration: JSTestDriver dialog box.

  4. Start the JSTestDriver server and capture a browser to run the tests in.
  5. On the main toolbar, select the JSTestDriver run configuration in the Run/Debug Configurations drop-down list and click the Run with Coverage button runWithCoverage.
  6. Monitor the code coverage in the Coverage tool window.
Measuring code coverage for tests executed on Karma
  1. Prepare tests manually or have tests generated by IntelliJ IDEA.
  2. Create a Karma configuration file karma.conf. For details, see Running Unit Tests on Karma.
  3. Create a run configuration of the type Karma.
  4. On the main toolbar, select the Karma run configuration in the Run/Debug Configurations drop-down list and click the Run with Coverage button runWithCoverage.
  5. Monitor the code coverage in the Coverage tool window. Note that when the tests are executed on Karma the Coverage tool window does not contain the Generate Coverage Report toolbar button exportToTextFile because a coverage report is actually generated on the disk every time Karma tests are run. The format of a coverage report can be configured in the configuration file, for example: 
    // karma.conf.js
module.exports = function(config) {

config.set({ ...

// optionally, configure the reporter

coverageReporter: { type : 'html', dir : 'coverage/' }

...

});};
    The following type values are acceptable:
    • html produces a bunch of HTML files with annotated source code
    • lcovonly produces an lcov.info file
    • lcov produces HTML + .lcov files. This format is applied by default.
    • cobertura produces a cobertura-coverage.xml file for easy Hudson integration
    • text-summary produces a compact text summary of coverage, typically to the console
    • text produces a detailed text table with coverage for all files