junit怎么用?

写了个很简单的测试用例,可是老是显示测试失败。netbean6.7.1
被测试类:
package javaapplication4;
public class NewClass {
public int add(int a,int b){
return a+b;
}
}

测试类
/*

  • To change this template, choose Tools | Templates
  • and open the template in the editor. */

package javaapplication4;
import junit.framework.TestCase;
public class NewClassTest extends TestCase {
public NewClassTest(String testName) {
super(testName);
}

@Override
protected void setUp() throws Exception {
    super.setUp();
}

@Override
protected void tearDown() throws Exception {
    super.tearDown();
}
/**
 * Test of add method, of class NewClass.
 */
public void testAdd() {
    System.out.println("add");
    int a = 3;
    int b = 4;
    NewClass instance = new NewClass();
    int expResult = 7;
    int result = instance.add(a, b);
    assertEquals(expResult, result);
    // TODO review the generated test code and remove the default call to fail.
    fail("The test case is a prototype.");
}

}

测试类基本都是netbean自己写的,现在测试老是显示失败
Tests run: 1, Failures: 1, Errors: 0, Time elapsed: 0.016 sec
------------- Standard Output ---------------
add


Testcase: testAdd(javaapplication4.NewClassTest): FAILED
The test case is a prototype.
junit.framework.AssertionFailedError: The test case is a prototype.
at javaapplication4.NewClassTest.testAdd(NewClassTest.java:42)
Test javaapplication4.NewClassTest FAILED

// TODO review the generated test code and remove the default call to fail.
应该和这句注释有关,这句话的意思: 检查产生的测试代码并且删除默认的fail 方法的调用,
所以你应该把 这句注释和fail方法的调用的这两行删掉。