Question

public Class Test{
   GetDataset(RandomBoolean uncertain);
   GetDataset2();
   GetDataset3();
}

where method definitions are

    public virtual void GetDataset2(){}
    public virtual void GetDataset3(){}

    public virtual void GetDataset(RandomBoolean uncertain)
    {
     if (uncertain.State){
            GetDataset2();
    }
     else{
       GetDataset3();
     }
    }

    //mocking uncertain.State to return true
    //ACT
    testObject.GetDataset(uncertainMock);

I want to test if GetDataset2() was called internally when I act on testObject.GetDataset();
I am not mocking the testObject because it’s the test object so if I try to do

testObject.AssertWasCalled(x => x.GetDataset2());

It won’t let me do this because testObject is not a mocked object.
I am using Rhino Mocks 3.5, I am definitely missing something here.
What is the best way to achieve this.

Answer 1

The short answer is: you can’t. On the other thing usually you don’t want to. When you are unit testing the class, you want to make sure that the class does its computation correctly and that it has correct side effects. You shouldn’t test the internals of the class, because this causes the coupling of the real code and the tests to be too strong. The idea is that you can freely change the implementation of your class and use your tests to make sure it still works correctly. You wouldn’t be able to do it if your tests inspect the internal state or flow.

You have 2 options (depending on context)

1. You can structure your tests in a way that they only look at externally visible behaviour
2. If (1) is too hard, consider refactoring GetDataset2 into a separate class. Then you would be able to mock it while testing GetDataset method.