Mocking class 中的一个动态方法

Question

I am pretty new to Mockito and Spring. I am trying to mock many methods of many classes. I want to create a functionality where bean name and method name can given as input as string, and it will throw same exception.

Example I have a class A and Class B

@Named
public Class A {
   public void methodInA() {
   System.out.println("In A"); 
  }
}

@Named
public Class B {
   public void methodInB() {
   System.out.println("In B"); 
  }
}

Below is what I am trying to do in test.

TestConfig:

@SpyBean
A a;

Test::

String className = "A";
String methodName = "methodInA";


Object bean = applicationContext.getBean("a");
Class clazzToSpy = bean.getClass();

Class[] paramTypes = clazzToSpy.getMethod(methodName);

Answer answer = new Answer() {
@Override
public Object answer(final InvocationOnMock invocationOnMock) throws Throwable {
   if(invocationOnMock.getMethod().getName().equals(methodName)) {
       throw new UnknownError("Manual Exception Created");
   }
   return invocationOnMock.callRealMethod();

  }
};

//Here I want to use the answer on the mock Something like below.

Method mockedMethod = clazzToSpy.getMethod(methodName, paramTypes);

Mockito.doAnswer(answer).when(mockedMethod)

I understand there is a gap in my understanding. How do I achieve something like above?

Has someone tried doing similar thing?

Related threads which I have tried:

1. Mocking Reflection based calls

2. Mocking getClass method with PowerMockito

3. mockito: mock method call with parameters by reflection

4. Mockito: is it possible to combine mock with a method name to create a methodCall inside a when() call?

5. Using Mockito to mock methods by reflection

Answer 1

This seems not going to work since when you:

@Spy
Method methodSpy;

Mockito throws:

 org.mockito.exceptions.base.MockitoException: Unable to initialize @Spy annotated field 'methodSpy'. Please ensure that the type 'Method' has a no-arg constructor.

and if you:

@Mock
Method methodMock;

it throws:

 org.mockito.exceptions.base.MockitoException: Cannot mock/spy class java.lang.reflect.Method Mockito cannot mock/spy because: - final class

at:

MockitoAnnotations.initMocks( this );