public void AddRange_Null () { ComboBox.ObjectCollection col = new ComboBox.ObjectCollection (new ComboBox ()); try { col.AddRange (null); Assert.Fail ("#1"); } catch (ArgumentNullException ex) { Assert.AreEqual (typeof (ArgumentNullException), ex.GetType (), "#2"); Assert.IsNull (ex.InnerException, "#3"); Assert.IsNotNull (ex.Message, "#4"); Assert.IsNotNull (ex.ParamName, "#5"); Assert.AreEqual ("items", ex.ParamName, "#6"); } }