public void Given_a_Trie_with_two_items_When_a_subitem_is_added_Then_it_has_three_items()
{
//Given
var trie = new StringTrie <string>();
trie.Add("Alpha", "first");
trie.Add("B", "second");
//When
trie.Add("Beta", "third");
Helper.WriteLine(trie.ToString());
//Then
var items = trie.ToArray();
AssertEqual(items[0], "Alpha", "first");
AssertEqual(items[1], "B", "second");
AssertEqual(items[2], "Beta", "third");
}