Mocking a base class method call with Moq

Question

I am modifiying a class method which formats some input paramater dates which are subsequently used as params in a method call into the base class (which lives in another as

Answer 1

It is quite possible mocking base class. But you will have to modify target class.

For ex. DerivedClass extends BaseClass. BaseClass has methods MethodA(), MethodB(), MethodC()... The DerivedClass has this method:

void MyMethod() {
  this.MethodA();
  this.MethodB();
  this.MethodC();
}

You want to mock base class in order to validate that all MethodA(), MethodB(), MethodC() are being called inside MyMethod().

You have to create a field in the DerivedClass:

class DerivedClass {
  private BaseClass self = this;
  ...
}

And also You have to modify the MyMethod():

void MyMethod() {
  self.MethodA();
  self.MethodB();
  self.MethodC();
}

Also add a method, which can inject the this.self field with Mock object

public void setMock(BaseClass mock) {
  this.self = mock;
}

Now you can mock:

DerivedClass target = new DerivedClass ();
BaseClass  mock = new  Mock(typeof(BaseClass));
target.setMock(mock);
target.MyMethod();

mock.verify(MethodA);
mock.verify(MethodB);
mock.verify(MethodC);

Using this technic, you can also mock nested method calls.