Karma

1. Download and install Node.js.

2. Make sure the JavaScript and TypeScript and Karma required plugins are enabled on the Settings | Plugins page, tab Installed, see Managing plugins for details.

1. Open the embedded Terminal (Ctrl+`) .

2. Type one of the following commands:

   • npm install if Karma and all the required plugins are already defined in package.json.

   • To install Karma and plugins as development dependencies:

     npm install --save-dev karma
     npm install --save-dev <karma_plugin> <another_karma_plugin>

To create a Karma configuration file

1. Open the Terminal and start the karma.conf.js generation wizard by typing one of the following depending on your operating system:

   • For macOS and Linux: ./node_modules/karma/bin/karma init

   • For Windows:

     npm install -g karma-cli
     karma init

2. Answering the questions of the wizard, specify the testing framework to use and the browsers to be captured automatically.

   See also Karma Files: Pattern matching.

To run a single test from the editor

• Click or in the left gutter and select Run <test_name> from the list.

  You can also see whether a test has passed or failed right in the editor, thanks to the test status icons and in the gutter.

To create a Karma run configuration

1. Open the Run/Debug Configuration dialog (Run | Edit Configurations on the main menu), click in the left-hand pane, and select Karma from the list. The Run/Debug Configuration: Karma dialog opens.

   tip

   Alternatively, select a test file in the Project tool window and select Create <filename> from the context menu.

2. Specify the Node.js interpreter to use.

   If you choose the Project alias, JetBrains Rider will automatically use the project default interpreter from the Node interpreter field on the Node.js page . In most cases, JetBrains Rider detects the project default interpreter and fills in the field itself.

   You can also choose another configured local or remote interpreter or click and configure a new one.

   Optionally specify the Node.js-specific option parameters and the environment variables to be passed to Node.js.

3. Specify the location of the karma package and the path to karma.conf.js.

4. Specify the working directory of the application. By default, the Working directory field shows the project root folder. To change this predefined setting, specify the path to the desired folder.

5. Specify the tests to run. This can be a specific test or suite, an entire test file, or a folder with test files.

6. Optionally, specify the command-line options that you want to pass to Karma to override the default settings from the karma.conf.js configuration file.

   For example, to run or debug tests in Headless Chrome, type --browsers ChromeHeadless in the Karma options field. See Automated testing with Headless Chrome for details.

   tip

   Alternatively, add 'ChromeHeadless' to the browsers option in karma.conf.js.

   To see all the available CLI options, type karma start --help in the Terminal Ctrl+`.

To run tests via a run configuration

1. Select the Karma run/debug configuration from the list on the main toolbar and click  to the right of the list.

2. Monitor test execution and analyze test results in the Test Runner tab of the Run tool window, see Explore test results for details.

To rerun failed tests

• In the Test Runner tab, click on the toolbar. JetBrains Rider will execute all the tests that failed during the previous session.

  

• To rerun a specific failed test, select Run <test name> on its context menu.

See Rerunning tests for details.

• To jump between a test and its subject or vice versa, open the file in the editor and select Go to | Test or Go to | Test Subject from the context menu, or just press N/A.

• To jump from a test result to the test definition, click the test name in the Test Runner tab twice, or select Jump to Source from the context menu, or just press F4. The test file opens in the editor with the cursor placed at the test definition.

• For failed tests, JetBrains Rider brings you to the failure line in the test from the stack trace. If the exact line is not in the stack trace, you will be taken to the test definition.

To start debugging a single test from the editor

• Click or in the left gutter and choose Debug <test_name> from the list.

To launch test debugging via a run/debug configuration

1. Create a Karma run/debug configuration as described above.

2. Select the Karma run/debug configuration from the list on the main toolbar and click  to the right of the list.

3. In the Debug window that opens, proceed as usual: step through the tests, stop and resume test execution, examine the test when suspended, run JavaScript code snippets in the Console, and so on.

To install karma-coverage

• In the embedded Terminal (Ctrl+`) , type:

  npm install  --save-dev karma-coverage

To add karma-coverage definition to the configuration file

1. Open karma.conf.js in the editor.

2. Locate the reporters definition and add coverage to the list of values in the format:

   reporters: ['progress', 'coverage']

3. Add a preprocessors definition and specify the coverage scope in the format:

   preprocessors: {'**/*.js': ['coverage']}

To launch tests with coverage

1. Create a Karma run/debug configuration as described above.

2. Select the Karma run/debug configuration from the list on the main toolbar and click  to the right of the list.

   Alternatively, use the test icons in the editor to quickly run a specific suite or a test with coverage.

   

3. Monitor the code coverage in the Coverage tool window.

   Every time Karma tests are run, a coverage report is actually generated on the disk. 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.