Question

I want to unit test following method

public void addRecord(Record record)  
{  
   Myclass newObj = new Mycalss();  
   // It creates newObj object, set some values using record object.  
   // and it adds the newObj in daatbase.
   dataReqDao.persist(newObj);
}    

I have mocked dataReqDao.persist method but how can I verify if right values are copied into newObj object? I want to get the newObj object.

I think thenAnswer will be the appropraite method to retrieve newObj ie method arguments but dont know how to use it method which returns void.

Update:
I tried

doAnswer(new Answer<Myclass>() {
              public Myclass answer(InvocationOnMock invocation) {
                  Object[] args = invocation.getArguments();
                  return (Myclass)args[0];
              }

        }).when(dataReqDao.persist(any(Myclass.class)));

EDIT:
It should be (Thanks David)

 doAnswer(new Answer<Myclass>() {
                  public Myclass answer(InvocationOnMock invocation) {
                      Object[] args = invocation.getArguments();
                      return (Myclass)args[0];
                  }

            }).when(dataReqDao).persist(any(Myclass.class));

Answer 1

You can create a custom argument matcher that would check fields of that object, or use an argument captor to capture the object for further inspection.

For example, as follows:

ArgumentCaptor<Myclass> c = ArgumentCaptor.forClass(Myclass.class);
verify(dateReqDao).persist(c.capture());
Myclass newObj = c.getValue();

... // Validate newObj