public void NullObjectAddressProperty()
 {
     var person = new Person("Bill Gates");
     Assert.That(person.Address.StreetAddress, Is.Not.Null);
 }
 public void NormalAddressProperty()
 {
     var person = new Person("Big bird", new Address("Seasame Street"));
     Assert.That(person.Address.StreetAddress, Is.Not.Null);
 }