Jest

1. Download and install Node.js.

2. Make sure the JavaScript and TypeScript plugin is enabled in the settings. Press Control+Alt+S to open the IDE settings and then select Plugins. Click the Installed tab. In the search field, type JavaScript and TypeScript. For more information about plugins, refer to Managing plugins.

• In the embedded Terminal (Alt+F12) , type:

  npm install --save-dev jest

Run a single test from the editor

• Click or in the 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.

Run all tests in a folder from the Project tool window

• In the Project tool window, select the folder with the tests, and then select Run 'Tests in <folder name>'.

  

Create a Jest run configuration

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

2. Specify the Node.js interpreter to use.

   If you choose the Project alias, IntelliJ IDEA will automatically use the project default interpreter from the Node interpreter field on the Node.js page . In most cases, IntelliJ IDEA 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.

3. Specify the location of the jest, react-scripts, react-script-ts, react-super-scripts, or react-awesome-scripts package.

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 jest.config.js or jest.config.ts file to use: select the relevant file from the list, or click and select it in the dialog that opens, or just type the path in the field.

   If the field is empty, IntelliJ IDEA looks for a package.json file with a jest key. The search is performed in the file system upwards from the working directory. If no appropriate package.json file is found, then a Jest default configuration is generated on the fly.

7. Optionally:

   Configure rerunning tests automatically on changes in the related source files. To do that, add the --watch flag in the Jest options field.

   You can also turn the watch mode on later by pressing the Watch for Changes toggle button in the Run tool window during a test session, refer to Rerun test automatically on changes (watch mode) below.

8. Optionally:

   Specify the environment variables for executing commands. IntelliJ IDEA will show these variables in completion lists for process.env.

   

9. In the Node options field, optionally type the Node.js-specific command-line options to be passed to the Node.js executable file. The acceptable options are:

   • Use --require coffeescript/register to have CoffeeScript files compiled into JavaScript on the fly during run.

     This mode requires that the register.js file, which is a part of the coffeescript package, is located inside your project. Therefore make sure you have the coffeescript package installed locally as described in Install the CoffeeScript compiler.

   • Use --inspect or --inspect-brk parameter when you are using Node.js v7 for Chrome Debugging Protocol support. Otherwise, by default the debug process will use V8 Debugging Protocol.

   • If you are using ECMAScript Modules in your project, IntelliJ IDEA detects them and adds the —experimental-vm-modules flag to the Node options field automatically.

Run tests via a run configuration

1. Select the Jest run/debug configuration from the list of configurations and click   in the list or on the toolbar.

2. Monitor test execution and analyze test results in the Test Runner tab of the Run tool window. For more information, refer to Explore test results.

Rerun failed tests

• In the Test Runner tab, click on the toolbar. IntelliJ IDEA 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.

Rerun tests automatically on changes (watch mode)

IntelliJ IDEA supports the watch mode in which a test is rerun automatically as soon as any changes are made to the test-related source file. As a result, you can just make changes to your code without having to rerun tests manually or restart the Jest run/debug configuration.

• In the Test Runner tab, press the Watch for Changes toggle button.

  

• Alternatively, add the --watch flag in the Jest options field of the run/debug configuration, refer to Create a Jest run configuration above.

• 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 Control+Shift+T.

• 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 caret placed at the test definition.

• To jump from a test or suite definition to its result in the Test Runner tab, click or in the gutter and choose Select <test_name> in Test Tree from the list.

  

• For failed tests, IntelliJ IDEA 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.

  

• Set the breakpoints where necessary.

• To start debugging a single test from the editor, click or in the gutter and select Debug <test_name> from the list.

• To start debugging all tests in a folder, select the folder in the Project tool window, and then select Debug 'Tests in <folder name>' from the context menu.

  

• To launch test debugging via a run/debug configuration, create a Jest run/debug configuration as described above. Then select the Jest run/debug configuration from the list of configurations and click   in the list or on the toolbar.

In the Debug tool 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.

Run tests with coverage

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

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

   Alternatively, quickly run a specific suite or a test with coverage from the editor: click or in the gutter and select Run <test_name> with Coverage from the list.

   

3. Monitor the code coverage in the Coverage tool window. The report shows how many files were covered with tests and the percentage of covered lines in them. From the report you can jump to the file and see what lines were covered – marked green – and what lines were not covered – marked red:

   

Before you start

1. Install and enable the Node.js Remote Interpreter plugin on the Settings | Plugins page, tab Marketplace, as described in Installing plugins from JetBrains Marketplace.

2. Make sure the Node.js and Docker required plugins are enabled on the Settings | Plugins page, tab Installed. For more information, refer to Managing plugins.

3. Download, install, and configure Docker as described in Docker

4. Configure a Node.js remote interpreter in Docker or via Docker Compose and set it as default in your project. Also make sure the package manager associated with this remote interpreter is set as project default.

5. Open your package.json and make sure Jest is listed in the devDependencies section:

   { "name": "node-express", "version": "0.0.0", "private": true, "dependencies": { "cookie-parser": "~1.4.4", "debug": "~2.6.9", "express": "~4.16.1", "http-errors": "~1.6.3", "morgan": "~1.9.1", "pug": "^3.0.2" }, "devDependencies": { "eslint": "^8.1.0", "http-server": "^14.0.0", "jest": "^27.3.1" } }

6. Right-click anywhere in the editor and select Run '<package manager> install' from the context menu.

Run tests

1. Create tests according to the instructions from the Jest official website.

2. Mark the folder where the unit tests are stored as a test source folder, see Content roots.

3. Proceed as with local development: run and debug single tests right from the editor or create a run/debug configuration to launch some or all of your tests as described in Run tests and Debug tests above.