Eclipse 中的“未找到 JUnit 测试”

所以我是JUnit的新手，我们必须用它来做家庭作业。我们的教授给了我们一个项目，有一个测试课， .当我右键单击>以JUnit测试>运行“时，我收到一个弹出错误，显示”找不到JUnit测试”。我知道这个问题已经在这里得到了回答（没有发现测试运行程序“JUnit 4”的测试），但是关闭日食，重新启动，清理和构建似乎不起作用。下面是我运行配置、生成路径和我正在尝试测试的类的屏幕截图。BallTest.java

BallTest.java

import static org.junit.Assert.*;
import junit.framework.Assert;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;
import org.junit.runner.JUnitCore; 
import org.junit.runner.Result; 
import org.junit.runner.notification.Failure; 

public class BallTest {

Ball ball;

/**
 * @throws java.lang.Exception
 */
@Before
public void setUp() throws Exception {
    System.out.println("Setting up ...");
    Point2D p = new Point2D(0,0);
    ball = new Ball(p);
}

/**
 * @throws java.lang.Exception
 */
@After
public void tearDown() throws Exception {
    System.out.println("Tearing down ...");
    ball = null;
}

/**
 * Test method for {@link Ball#getCoordinates()}.
 */
@Test
public void testGetCoordinates() {
    assertNotNull(ball); // don't need Assert. because of the import statement above.
    Assert.assertEquals(ball.getCoordinates().getX(), 0);
    Assert.assertEquals(ball.getCoordinates().getY(), 0);
}

/**
 * Test method for {@link Ball#setCoordinates(Point2D)}.
 */
@Test
public void testSetCoordinates() {
    Assert.assertNotNull(ball);
    Point2D p = new Point2D(99,99);
    ball.setCoordinates(p);
    Assert.assertEquals(ball.getCoordinates().getX(), 99);
    Assert.assertEquals(ball.getCoordinates().getY(), 99);
}

/**
 * Test method for {@link Ball#Ball(Point2D)}.
 */
@Test
public void testBall() {
    Point2D p = new Point2D(49,30);
    ball = new Ball(p);
    Assert.assertNotNull(ball);
    Assert.assertEquals(ball.getCoordinates().getX(), 49);
    Assert.assertEquals(ball.getCoordinates().getY(), 30);

    //fail("Not yet implemented");
}

public static void main (String[] args) {
         Result result = JUnitCore.runClasses(BallTest.class);
         for (Failure failure : result.getFailures()) { 
                System.out.println(failure.toString()); 
            } 
        System.out.println(result.wasSuccessful());  
}

}