How do I mock an abstract base class constructor

[Mike]

I am trying to test a derived class constructor, but keep hitting code in the base class constructor  This post(https://www.telerik.com/forums/mock-base-class-constructor#PUXW928ic0SPaEl3wK8Mxg) shows how to mock a base class constructor, but it does not work if the base class is abstract.

[Mike]

I found that this was happening because I did not future mock the derived class constructo. e.g. :

Mock.Arrange(() => new DerivedClass(<constructor arguments>)).CallOriginal().MustBeCalled();