public void CanFindTheOldest()
        {
            Person oldestReal, oldestCalculated;

            oldestReal = (from person in persons
                          orderby person.BirthDate ascending
                          select person).FirstOrDefault();

            oldestCalculated = addressBookBusiness.FindOldest();

            addressBookRepositoryMock.Verify(abr => abr.RetrieveAllPersons(), Times.Once);
            Assert.AreSame(oldestReal, oldestCalculated);
        }
        private void ConfigureForFindOldestCommand(CommandLineApplication cla)
        {
            cla.Command("findoldest", (application) =>
            {
                application.Description = "With this command you can find the oldest person.";
                application.OnExecute(() =>
                {
                    if (cla.OptionHelp.HasValue())
                    {
                        application.ShowHelp("findoldest");
                        return(0);
                    }

                    Person person = addressBookBusiness.FindOldest();
                    person.Print();
                    return(0);
                });
            });
        }