public void When_Mapping_With_Conversion_Then_Maps() { // Arrange var sut = new Mapper(); sut.BuildClassMap<ConversionFrom, ConversionTo>(); sut.BuildConversion<string, int>().Explictly(x => x.Count()); var from = new ConversionFrom {Age = "Twelve"}; var to = new ConversionTo {Age = 6}; // Act sut.Merge(from, to); // Assert Assert.AreEqual(from.Age.Count(), to.Age); }