Solving the “TestEngine with ID ‘junit-jupiter’ failed to discover tests” Conundrum in Maven Configuration

Are you tired of scratching your head over the cryptic error message “TestEngine with ID ‘junit-jupiter’ failed to discover tests” in your Maven project? You’re not alone! This frustrating issue has puzzled many a developer, but fear not, dear reader, for we’re about to embark on a journey to vanquish this error once and for all.

What’s Behind the Error?

Before we dive into the solutions, let’s take a step back and understand what’s causing this error. The “TestEngine with ID ‘junit-jupiter’ failed to discover tests” error typically occurs when Maven is unable to find or execute JUnit tests in your project. This can happen due to various reasons, including:

• Missing or incorrect dependencies in the pom.xml file
• Incorrect test class or method naming conventions
• Missing or incorrect annotations in test classes
• Conflicting test engines or dependencies
• Corrupted project setup or caching issues

Troubleshooting Steps

Now that we’ve covered the possible causes, let’s walk through a series of troubleshooting steps to help you identify and resolve the issue:

Step 1: Verify Dependencies

First, ensure that you have the correct dependencies in your pom.xml file. Specifically, you need to include the following:

<dependencies>
    <dependency>
        <groupId>junit</groupId>
        <artifactId>junit</artifactId>
        <version>4.13</version>
        <scope>test</scope>
    </dependency>
    <dependency>
        <groupId>org.junit.jupiter</groupId>
        <artifactId>junit-jupiter-engine</artifactId>
        <version>5.8.2</version>
        <scope>test</scope>
    </dependency>
</dependencies>

If you’re using a different version of JUnit or JUnit Jupiter, make sure to adjust the versions accordingly.

Step 2: Check Test Class and Method Naming Conventions

Next, ensure that your test class and method names follow the correct conventions:

• Test class names should start with the prefix “Test” (e.g., “TestMyClass”)
• Test method names should start with the prefix “test” (e.g., “testMyMethod”)

Step 3: Verify Annotations

Make sure that your test classes and methods are properly annotated with the following:

@RunWith(JUnitPlatform.class)
public class MyTest {
    @Test
    public void myTest() {
        // test code here
    }
}

Notice the @RunWith(JUnitPlatform.class) annotation at the class level and the @Test annotation at the method level.

Step 4: Check for Conflicting Dependencies

If you’re using other testing frameworks or dependencies, ensure that they’re not conflicting with JUnit Jupiter. Try excluding or removing any conflicting dependencies to isolate the issue.

Step 5: Clean and Rebuild the Project

Sometimes, a simple clean and rebuild of the project can resolve the issue. Run the following command in your terminal:

mvn clean package

This will remove any cached files and recompile the project.

Common Solutions

Based on the troubleshooting steps above, here are some common solutions to the “TestEngine with ID ‘junit-jupiter’ failed to discover tests” error:

Solution 1: Update JUnit Jupiter Version

If you’re using an older version of JUnit Jupiter, try updating to the latest version:

<dependency>
    <groupId>org.junit.jupiter</groupId>
    <artifactId>junit-jupiter-engine</artifactId>
    <version>5.8.2</version>
    <scope>test</scope>
</dependency>

Solution 2: Exclude Transitive Dependencies

If you’re using other testing frameworks or dependencies that are transitively including older versions of JUnit, try excluding them:

<dependency>
    <groupId>junit</groupId>
    <artifactId>junit</artifactId>
    <version>4.13</version>
    <scope>test</scope>
    <exclusions>
        <exclusion>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
        </exclusion>
    </exclusions>
</dependency>

Solution 3: Use the Correct TestRunner

Ensure that you’re using the correct TestRunner for JUnit Jupiter:

@RunWith(JUnitPlatform.class)
public class MyTest {
    // test code here
}

Conclusion

We’ve covered the possible causes and troubleshooting steps for the “TestEngine with ID ‘junit-jupiter’ failed to discover tests” error. By following these steps and applying the common solutions, you should be able to resolve the issue and get your JUnit tests running successfully in your Maven project.

Remember to stay vigilant and methodical in your troubleshooting approach, and don’t be afraid to experiment and try different solutions until you find the one that works for you.

Error Message	Troubleshooting Steps	Solution
TestEngine with ID ‘junit-jupiter’ failed to discover tests	Verify dependencies, test class and method naming conventions, annotations, and conflicting dependencies	Update JUnit Jupiter version, exclude transitive dependencies, or use the correct TestRunner

Happy coding, and may the testing forces be with you!

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