public void AsLookup()
{
var a = new System.Collections.Specialized.NameValueCollection {
{ "1", "one" },
{ "1", "uno" },
};
var l = a.AsLookup();
Assert.AreEqual(1, l.Count);
Assert.AreEqual(2, l["1"].Count());
Assert.AreEqual(0, l["2"].Count());
a.Add("2", "dos");
Assert.AreEqual(2, l.Count);
Assert.AreEqual(1, l["2"].Count());
}