public virtual void TestSet()
{
RefList <Ref> one = ToList(REF_A, REF_A);
RefList <Ref> two = one.Set(1, REF_B);
NUnit.Framework.Assert.AreNotSame(one, two);
// one is not modified
NUnit.Framework.Assert.AreEqual(2, one.Size());
NUnit.Framework.Assert.AreSame(REF_A, one.Get(0));
NUnit.Framework.Assert.AreSame(REF_A, one.Get(1));
// but two is
NUnit.Framework.Assert.AreEqual(2, two.Size());
NUnit.Framework.Assert.AreSame(REF_A, one.Get(0));
NUnit.Framework.Assert.AreSame(REF_B, two.Get(1));
}