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

```java
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?

[![enter image description here](https://i.stack.imgur.com/p7I9T.png)](https://i.stack.imgur.com/p7I9T.png)

Answer: 
Right click the java file and choose:

**Build Path -> Configure Build Path -> Java Build Path**.

Choose the tab **Libraries** in Java Build Path, On the right side tab choose **Add Library**.

Select **JUnit** and click **Next**.

Choose **JUnit 5** in **JUnit Library version** dropdown and click **finish**.

Now run the Test with **Junit Test**, it will work.

This procedure worked for me.
Adding the JUnit vintage dependency fixed the issue for me.

<https://junit.org/junit5/docs/current/user-guide/#migrating-from-junit4-running>

```
    <dependency>
        <groupId>org.junit.vintage</groupId>
        <artifactId>junit-vintage-engine</artifactId>
        <scope>test</scope>
    </dependency>   

```