public void sendLetterTest()
{
objCity = new City("Starling");
Letter objLetter = new SimpleLetter(new Sender(objCity.listHabitant[0]), new Receiver(objCity.listHabitant[1]), "bla bla");
objCity.sendLetter(objLetter);
Assert.AreEqual(1, objCity.getNumberOfLetter());
}
public void createSimpleLetter(Inhabitant prmReceiver, String prmContent)
{
Letter objLetterTemp = new SimpleLetter(new Sender(this), new Receiver(prmReceiver), prmContent);
this.postLetter(prmReceiver, objLetterTemp);
}