Eclipse Oxygen.3中JUnit 5测试运行器提示“未找到测试”求助

Hey there, let's get to the bottom of that frustrating error you're seeing! The core issue here is that your test class uses JUnit 4 annotations and APIs, but Eclipse is trying to run it with the JUnit 5 test runner—they don't play well together out of the box. Here's how to fix it step by step:

1. Verify Your JUnit Dependencies #

First, make sure your project has the correct JUnit 4 libraries attached:

• Right-click your project → Build Path → Configure Build Path
• Go to the Libraries tab and check if you have a JUnit 4 library (like JUnit 4.x) listed. If not, add it by clicking Add Library → JUnit → Select JUnit 4 and finish.
• If you're using Maven, double-check your pom.xml to ensure you're pulling in JUnit 4, not JUnit 5:

  <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>4.13.2</version>
      <scope>test</scope>
  </dependency>
  

2. Switch the Test Runner in Eclipse #

This is the most likely fix for your error:

• Right-click your MyMathTest class → Run As → Run Configurations...
• In the left pane, select the JUnit configuration for your test (or create a new one if needed)
• In the right pane, look for the Test runner dropdown menu—select "JUnit 4" instead of "JUnit 5"
• Click Apply then Run—your tests should now be detected!

3. Tweak Your Test Class (Optional but Recommended) #

Your current test class uses default package visibility (no public modifier). While JUnit 4 technically allows this, Eclipse can sometimes have trouble detecting non-public test classes. Try updating your class definition to:

public class MyMathTest {
    // rest of your code stays the same
}

Also, double-check that you're importing the JUnit 4 @Test annotation:

// Correct JUnit 4 import
import org.junit.Test;

// NOT the JUnit 5 import
// import org.junit.jupiter.api.Test;

Quick Look at Your Test Code #

For reference, here's your code with the minor visibility tweak noted:

import static org.junit.Assert.assertEquals;
import org.junit.After;
import org.junit.AfterClass;
import org.junit.Before;
import org.junit.BeforeClass;
import org.junit.Test;

public class MyMathTest { // Added public modifier
    MyMath myMath = new MyMath();

    @Before
    public void before() {
        System.out.println("Before");
    }

    @After
    public void after() {
        System.out.println("After");
    }

    @Test
    public void testSum_with3numbers() {
        System.out.println("Test1");
        // Don't forget to add your assertion logic here!
        // Example: assertEquals(6, myMath.sum(1, 2, 3));
    }
}

Give these steps a try—switching the test runner to JUnit 4 should resolve the "no tests found" error immediately.

内容的提问来源于stack exchange，提问作者Leem