public void MenuItemCollection_IndexOfKey_Invoke_ReturnsExpected(string key, int expected) { var menu = new SubMenu(new MenuItem[] { new MenuItem { Name = "name" } }); var collection = new Menu.MenuItemCollection(menu); Assert.Equal(expected, collection.IndexOfKey(key)); // Call again to validate caching behaviour. Assert.Equal(expected, collection.IndexOfKey(key)); Assert.Equal(-1, collection.IndexOfKey("noSuchKey")); }