Running JUnit Tests in IntelliJ #

When running JUnit tests in IntelliJ, you may see an error such as:

InaccessibleObjectException: Unable to make … accessible:

module … does not "opens …" to module org.junit.platform.commons

This happens because newer IntelliJ does not automatically place JUnit on the module path for modular projects.

Follow these steps:

1. Open module-info.java.

2. Find the following line and uncomment it:

   // Uncomment the following line when running tests in IntelliJ:

   // requires org.junit.jupiter.api;

3. IntelliJ will now highlight the requires org.junit.jupiter.api; line in red.

4. Place your cursor on the red underline. IntelliJ will show a quick-fix option:

   Add library org.junit.jupiter.api to classpath

5. Click this option. IntelliJ will configure the test module path automatically.

After this, JUnit tests will run normally.

Note: This IntelliJ configuration is local and not portable.

Test Warning (Mockito) #

When running tests using Mockito, you may see a Java agent warning.

• This is caused by internal mechanisms used for mocking.
• It does not affect test results.
• No action is required 😄.