Thanks for your answer :)
Unfortunately, this requires modifying the existing code which I'm not keen on doing until I have some stable unit tests in place. However, the following seems to be a solution which works for me:
public class Base
{
public void BaseMethod()
{
throw new NotImplementedException("BaseMethod not implemented!!");
}
}
public class Derived : Base
{
public Derived()
{
BaseMethod();
}
}
[TestMethod]
public void TestMethod1()
{
Derived fakeDerived = Isolate.Fake.NextInstance<Derived>(Members.CallOriginal, ConstructorWillBe.Called);
Base fakeBase = (Base)fakeDerived;
Isolate.WhenCalled(() => fakeBase.BaseMethod()).IgnoreCall();
Derived derived = new Derived();
}