public void Apply_CopiesValueFromSourceToTarget() { var propertyMapping = new PropertyMapping <Source, Target, string>(string.Empty, t => t.TargetValue, (s, t) => t.TargetValue = s.SourceValue, string.Empty); var source = new Source(); var target = new Target(); propertyMapping.Apply(source, target); target.TargetValue.Should().Be("Source"); }