模拟接口方法中的空指针异常 [英] Null Pointer Exception in mocking Interface method

问题描述

我使用 TestNG 进行测试，使用 JMockit 来模拟 mockMethod().这是测试用例:

I'm using TestNG for testing and JMockit for mocking mockMethod(). Here's the test case:

@Test
public void testClass1() {
    new MockUp<MyInterface>() {
    @Mock
    public int myMethod(final MyObject someObject ){
         return 0;
        }
    };

    MyObject obj = new MyObject();
    Assert.assertEquals(obj.mockMethod(someObject),0); 
    }
}

我为 assertEquals() 调用的 mockMethod() 看起来像这样:

The mockMethod() I'm calling for assertEquals() looks like this:

public class Class1 {
      MyInterface my;
      public int mockMethod(final MyObject someObject ){
             ......  //processing steps
             return my.myMethod(someObject);
      }
}

测试用例抛出空指针异常.我究竟做错了什么?我是否模拟了 mockMethod() 的实现?我也试过了，没用.

Test case throws a Null pointer exception. What am I doing wrong? Do I mock the implementation of mockMethod()? I tried that too, but it hasn't worked.

推荐答案

JMockit 创建了 MyInterface 的模拟实例，但您的测试从未使用过它.可以通过MockUp#getInstance()方法获取.那么当然测试也需要将实例传递给被测类.

JMockit created a mock instance of MyInterface, but your test never used it. It can be obtained through the MockUp#getInstance() method. Then of course the test also needs to pass the instance to the class under test.

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