Eclipse keep saying “No tests found with test runner JUnit 5”

Question

I am using Eclipse Oxygen.3 Release (4.7.3). The following is my JUnit test class:

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;

class MyMathTest {
    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");
        int result = myMath.sum(new int[] {1,2,3});
        int expected = 6;
        assertEquals(expected, result);
    }

    @Test
    public void testSum_with1numbers() {
        System.out.println("Test2");
        int result = myMath.sum(new int[] {3});
        int expected = 3;
        assertEquals(expected, result);
    }

    @BeforeClass
    public static void beforeClass() {
        System.out.println("Before class");
    }

    @AfterClass
    public static void afterClass() {
        System.out.println("After class");
    }

}

When I run this Junit test, eclipse keeps popping up dialog telling "No tests found with test runner 'JUnit 5'". Why?

Answer 1

Your test class is currently based on JUnit 4 since it uses annotations from the org.junit package.

Thus, to get it to run as a JUnit 4 test class in Eclipse, you need to select the JUnit 4 Runner in the "Run Configuration". Click on the tiny arrow (pointing down) next to the green circle with a white arrow in it (at the top of the Eclipse IDE). There you should see your test class, and by selecting that you can switch between the JUnit 4 and JUnit 5 runners.

On the other hand, if your goal is to write a test using JUnit Jupiter (i.e., the programming model for JUnit 5), you'll need to switch from annotations in org.junit to org.junit.jupiter.api.

Answer 2

Take a look back to your imports.

You imports import org.junit.Test; (Used for run test cases with JUnit 4)

You need to import import org.junit.jupiter.api.Test; to run tast case with JUnit5.

Answer 3

In Eclipse 2019-09 (4.13) is a bug that can cause the "No tests found with test runner 'JUnit 5'" error: https://bugs.eclipse.org/bugs/show_bug.cgi?id=551298

I added the following dependency to my project and it worked for me:

<dependency>
    <groupId>org.junit.platform</groupId>
    <artifactId>junit-platform-commons</artifactId>
    <version>1.5.2</version><!--$NO-MVN-MAN-VER$-->
    <scope>test</scope>
</dependency>

Answer 4

You are using JUnit 4 annotations with JUnit 5 dependencies. If you want to use JUnit 5 you should replace:
'@Before' with '@BeforeEach'
'@AfterEach' with '@AfterEach'
'@BeforeAll' with '@BeforeAll'
'@AfterAll' with '@AfterAll'

Here is more about JUnit 5 annotations https://junit.org/junit5/docs/current/user-guide/#writing-tests-annotations/

Answer 5

This happened to me because my test method was declared as private and JUnit could not detect it. After I made it public it worked as expected, of course with @Test annotation.