public void Can_Cast_Spec_To_Base_Class()
        {
            BaseClass implicitCast = new MixinIsTargetsNestedClassSpec();
            implicitCast.ShouldNotBeNull();

            var explicitCast = (BaseClass) _spec;
            explicitCast.ShouldNotBeNull();
        }
 protected override void Establish_context()
 {
     _spec = new MixinIsTargetsNestedClassSpec();
 }