public void UpcastSet_implements_ICollection_of_Base()
{
ICollection<Base> upcasted = new UpCastSet<Derive, Base>();
Assert.AreEqual(false, upcasted.IsReadOnly);
Assert.AreEqual(0, upcasted.Count);
//Adds an element
var d = new Derive(1);
upcasted.Add(d);
Assert.AreEqual(1, upcasted.Count);
Assert.AreEqual(true, upcasted.Contains(d));
//CopyTo copies all elements to an array of Base
var a1 = new Base[1];
upcasted.CopyTo(a1, 0);
Assert.AreSame(d, a1[0]);
//Removes the element
upcasted.Remove(d);
Assert.AreEqual(0, upcasted.Count);
Assert.AreEqual(false, upcasted.Contains(d));
//CopyTo copies nothing after all elements are removed
var a2 = new Base[0];
upcasted.CopyTo(a2, 0);
Assert.AreEqual(0, a2.Count());
var b = new Base(1);
Assert.Throws<InvalidCastException>(() => upcasted.Add(b));
Assert.Throws<InvalidCastException>(() => upcasted.Remove(b));
}
public void UpcastSet_throws_when_working_on_Base()
{
ICollection<Base> upcasted = new UpCastSet<Derive, Base>();
var b = new Base(1);
Assert.Throws<InvalidCastException>(() => upcasted.Add(b));
Assert.Throws<InvalidCastException>(() => upcasted.Remove(b));
Assert.Throws<InvalidCastException>(() => { var flag = upcasted.Contains(b); });
}