public void Handle_WhenEmpty_ReturnAbsentFunctionValue()
{
var handlePresent = new MockFunction <string>().RunReturns("present");
var handleAbsent = new MockFunction <string>().RunReturns("absent");
var option = Optional <string> .Empty();
var result = option.Handle(value => handlePresent.Run(), () => handleAbsent.Run());
Assert.Equal("absent", result);
handlePresent.VerifyFunctionNotCalled();
handleAbsent.VerifyFunctionCalled();
}