EasyMock模拟方法调用在重置模拟对象后第二次调用时返回null

这是我在Stackoverflow的第一篇帖子,到目前为止,我一直是这个论坛的活跃读者,我在这里发布了我的第一个问题。

这是关于EasyMock的使用,我是EasyMok的新用户,在下面的示例代码中,我正在为返回具有相同对象的合作者方法设置期望值(无论是相同对象还是不同对象,但结果是相同的),并且在退出测试方法之前我正在重置。但当执行第二个测试时,mocked方法返回null,我不确定为什么会发生这种情况。

如果我运行这些方法

@RunWith(PowerMockRunner.class)
@PrepareForTest({CollaboratorWithMethod.class, ClassTobeTested.class})
public class TestClassTobeTested {

private TestId testId = new TestId();

 @Test
public void testMethodtoBeTested() throws Exception{
    CollaboratorWithMethod mockCollaborator = EasyMock.createMock(CollaboratorWithMethod.class);
    PowerMock.expectNew(CollaboratorWithMethod.class).andReturn(mockCollaborator);
    EasyMock.expect(mockCollaborator.testMethod("test")).andReturn(testId);
    PowerMock.replay(CollaboratorWithMethod.class);
    EasyMock.replay(mockCollaborator);
    ClassTobeTested testObj = new ClassTobeTested();
    try {
        testObj.methodToBeTested(); 
    } finally {
        EasyMock.reset(mockCollaborator);
        PowerMock.reset(CollaboratorWithMethod.class);
    }
}  

@Test
public void testMothedtoBeTestWithException() throws Exception {
    CollaboratorWithMethod mockCollaborator = EasyMock.createMock(CollaboratorWithMethod.class);
    PowerMock.expectNew(CollaboratorWithMethod.class).andReturn(mockCollaborator);
    EasyMock.expect(mockCollaborator.testMethod("test")).andReturn(testId);
    PowerMock.replay(CollaboratorWithMethod.class);
    EasyMock.replay(mockCollaborator);
    ClassTobeTested testObj = new ClassTobeTested();
    try {
        testObj.methodToBeTested();
    } finally {
        EasyMock.reset(mockCollaborator);
        PowerMock.reset(CollaboratorWithMethod.class);
    }
}

}

这是我的合作者课程

public class CollaboratorWithMethod {
   public TestId testMethod(String text) throws IllegalStateException {
     if (text != null) {
        return new TestId();
     } else {
        throw new IllegalStateException();
     }
  }
}

这是我要考的课

public class ClassTobeTested {

public static final CollaboratorWithMethod collaborator = new CollaboratorWithMethod();

public void methodToBeTested () throws IOException{
    try {
        TestId testid = collaborator.testMethod("test");
        System.out.println("Testid returned "+ testid);
    } catch (IllegalStateException e) {
        throw new IOException();
    }
}
}

我正在寻求你们的帮助,以了解这里到底发生了什么