public void ShouldMapIntPropToNullableInt() { var data = new Model2 { IntProp = 123 }; var mapper = new ObjectMapper <Model2, Dto2>(); mapper.Append(p => p.IntProp, p => (int?)p.IntProp); var target = data.Map(mapper); target.Should().BeEquivalentTo(new Dto2() { IntProp = 123 }); }