public void AddRange() { StringStringDictionary dictionary = new StringStringDictionary(); dictionary.Add(new StringStringPair("four", "fourth value")); dictionary.Add(new StringStringPair("five", "fifth value")); Assert.Throws <NotSupportedException>(() => _readOnly.AddRange(dictionary)); _dictionary.AddRange(dictionary); Assert.AreEqual(5, _dictionary.Count); Assert.IsTrue(_dictionary.ContainsKey("four")); Assert.IsTrue(_dictionary.ContainsValue("fourth value")); Assert.IsTrue(_dictionary.ContainsKey("five")); Assert.IsTrue(_dictionary.ContainsValue("fifth value")); Assert.Throws <ArgumentException>(() => _dictionary.AddRange(dictionary)); }