public void TestChangeName()
{
Person p = new Person();
PersonObserver ob = new PersonObserver();
p.PropertyChanged += ob.PropertyChanged;
p.Name = "H";
Assert.AreEqual("Name", ob.ChangedName);
}
public void TestChangeAge()
{
Person p = new Person();
PersonObserver ob = new PersonObserver();
p.PropertyChanged += ob.PropertyChanged;
p.Age = 0;
Assert.AreEqual(null, ob.ChangedName);
p.Age = 3;
Assert.AreEqual("Age", ob.ChangedName);
}