public void TestGetAgeDifferenceError()
{
var personList = new List <Person> {
new Person {
Name = "George", Gender = "Male", DateOfBirth = Convert.ToDateTime("01/01/2001")
}, new Person {
Name = "Beck", Gender = "Male", DateOfBirth = Convert.ToDateTime("01/01/2000")
}
};
_addressBookLoader.Setup(c => c.LoadAddressBook()).Returns(personList);
classUnderTest = new AddressBookService(_addressBookLoader.Object, _logger.Object);
var result = classUnderTest.GetAgeDifference("Beck", "Jack");
Assert.Null(result.Result);
}