Preparing to Use Karma Test Runner

The Karma test runner supports executing unit tests against the Node.js server. The tests themselves can use Jasmine, QUnit, or Mocha libraries in Karma-specific edition.

Besides running unit tests, with Karma you can measure how much of your code is covered with tests. For more details, see Monitoring Code Coverage for JavaScript. To run tests with coverage, you need an additional Karma-related package.

The easiest way to install the Karma test runner is to use the Node Package Manager (npm), which is a part of Node.js. See Installing and Removing External Software Using Node Package Manager for details.

Depending on the desired location of the Karma test runner executable file, choose one of the following methods:

• Install the test runner globally at the IntelliJ IDEA level so it can be used in any IntelliJ IDEA project.
• Install the test runner in a specific project and thus restrict its use to this project.
• Install the test runner in a project as a development dependency.

In either installation mode, make sure that the parent folder of the Karma test runner is added to the PATH variable. This enables you to launch the test runner from any folder.

IntelliJ IDEA provides user interface both for global and project installation as well as supports installation through the command line.

On this page:

• Preparing to Install the Karma Test Runner
• Installing Karma Globally
• Installing Karma in a Project
• Configuring Testing Frameworks in a Project

Preparing to Install the Karma Test Runner

1. Download and install Node.js. The runtime environment is required for two reasons:
   • The Karma test runner is started through Node.js.
   • NPM, which is a part of the runtime environment, is also the easiest way to download the Karma test runner.

   If you are going to use the command line mode, make sure the path to the parent folder of the Node.js executable file and the path to the npm folder are added to the PATH variable. This enables you to launch the Karma test runner and npm from any folder.

2. Install and enable the NodeJS repository plugin as described in Installing, Updating and Uninstalling Repository Plugins and Enabling and Disabling Plugins.
3. Install and enable the Karma repository plugin. The plugin is not bundled with IntelliJ IDEA, but it can be installed from the JetBrains plugin repository as described in Installing, Updating and Uninstalling Repository Plugins and Enabling and Disabling Plugins.

Installing Karma Globally

Global installation makes a test runner available at the IntelliJ IDEA level so it can be used in any IntelliJ IDEA project. Moreover, during installation the parent folder of the test runner is automatically added to the PATH variable, which enables you to launch the test runner from any folder. To install the test runner globally, do one of the following:

• Run the installation from the command line in the global mode:
  1. Launch the embedded Terminal by hovering your mouse pointer over in the lower left corner of IntelliJ IDEA and choosing Terminal from the menu (see Working with Embedded Local Terminal for details).
  2. Switch to the directory where NPM is stored or define a PATH variable for it so it is available from any folder, see Installing NodeJs.
  3. Type the following command at the command line prompt:
     npm install -g karma

     The -g key makes the test runner run in the global mode. Because the installation is performed through NPM, the Karma test runner is installed in the npm folder. Make sure this parent folder is added to the PATH variable. This enables you to launch the test runner from any folder.

     For more details on the NPM operation modes, see npm documentation. For more information about installing the Karma test runner, see https://npmjs.org/package/karma.

• Run NPM from IntelliJ IDEA using the Node.js and NPM page of the Settings dialog box.
  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 packagePage page that opens, the Packages area shows all the engineDependent packages that are currently installed on your computer, both at the global and at the project level. Click .
  3. In the Available Packages dialog box that opens, select the required package to install.
  4. Select the Options check box and type -g in the text box next to it.
  5. Optionally specify the product version and click Install Package to start installation.

Installing Karma in a Project

Installing a test runner in a specific project restricts its use to this project. To run project installation, do one of the following:

• Run the installation from the command line:
  1. Launch the embedded Terminal by hovering your mouse pointer over in the lower left corner of IntelliJ IDEA and choosing Terminal from the menu (see Working with Embedded Local Terminal for details).
  2. Switch to the project root folder and type the following command at the command line prompt:
     npm install karma
• Run NPM from IntelliJ IDEA using the Node.js and NPM page of the Settings dialog box.
  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, the Packages area shows all the Node.js-dependent packages that are currently installed on your computer, both at the global and at the project level. Click .
  3. In the Available Packages dialog box that opens, select the required package.
  4. Optionally specify the product version and click Install Package to start installation.

Project level installation is helpful and reliable in template-based projects of the type Node Boilerplate or Node.js Express, which already have the node_modules folder. The latter is important because NPM installs the Karma test runner in a node_modules folder. If your project already contains such folder, the Karma test runner is installed there.

Projects of other types or empty projects may not have a node_modules folder. In this case npm goes upwards in the folder tree and installs the Karma test runner in the first detected node_modules folder. Keep in mind that this detected node_modules folder may be outside your current project root.

Finally, if no node_modules folder is detected in the folder tree either, the folder is created right under the current project root and the Karma test runner is installed there.

In either case, make sure that the parent folder of the Karma test runner is added to the PATH variable. This enables you to launch the test runner from any folder.

Configuring Testing Frameworks in a Project

1. Download the Jasmine, QUnit, or Mocha framework. The easiest way is to use the Node.js Package Manager:
   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 karma-jasmine, karma-qunit, or karma-mocha package and click Install Package. Close the dialog box when ready. IntelliJ IDEA returns to the Node.js page, where the selected package is added to the Packages list. Click OK.
2. To enable IntelliJ IDEA to resolve references to the downloaded framework and provide code completion and other types of coding assistance, configure the framework as a IntelliJ IDEA JavaScript library.