public void GetKey ()
		{
			CustomErrorCollection col = new CustomErrorCollection ();

			col.Add (new CustomError (404, "http://404-error.com/"));

			Assert.AreEqual ("404", col.GetKey (0), "A1");
		}
		public void GetKey_OutOfRange ()
		{
			CustomErrorCollection col = new CustomErrorCollection ();
			Assert.IsNull (col.GetKey(0), "A1");
		}