IntelliJ IDEA is a popular Integrated Development Environment (IDE) for Java developers that includes built-in support for running tests. Here are the steps to run tests with IntelliJ IDEA:

1. Create a test configuration: In IntelliJ IDEA, you can create a test configuration that specifies the test classes or methods that you want to run, as well as any other options such as the classpath and test output directory. To create a test configuration, go to the "Run" menu and select "Edit Configurations...". Then, click the "+" button and select "JUnit" to create a new JUnit test configuration.

2. Specify the test class or method: In the test configuration dialog, you can specify the test class or method that you want to run. You can either select the test class from a list of classes in your project, or you can enter the fully-qualified name of the class. You can also specify individual test methods by name.

3. Configure the classpath: The classpath for your tests may be different from the classpath for your main application. You can specify the classpath for your tests in the "Classpath" tab of the test configuration dialog.

4. Configure other options: You can configure other options for your test configuration, such as the working directory, the test output directory, and the environment variables.

5. Run the tests: Once you have created your test configuration, you can run the tests by clicking the "Run" button in the toolbar or by selecting "Run" from the "Run" menu. IntelliJ IDEA will compile your code, run the tests, and display the results in the test runner window.

In addition to running tests with IntelliJ IDEA, you can also use the IDE to create and edit tests, debug failing tests, and view the test results in a variety of formats. This makes it easy to test and debug your Java code in a convenient and efficient way.