public void ChangeFlyAbility_ShouldReturnTheOposite()
{
eagle.SetFlyable(canNotFly);
cat.SetFlyable(canFly);
string eagleResult = eagle.TryTFly();
string catResult = cat.TryTFly();
Assert.AreEqual(canNotFly.Fly(), eagleResult);
Assert.AreEqual(canFly.Fly(), catResult);
}