public void ConvertAll()
{
var deque = new Deque <int>(new[] { 1, 2, 3, 4 });
var deque_str = deque.ConvertAll(_ => _ + "");
Assert.Equal(4, deque_str.Count);
Assert.Equal(new[] { "1", "2", "3", "4" }, deque_str);
deque = new Deque <int>(new[] { 1, 2, 3, 4 });
Assert.Equal(4, deque.RemoveFromBack());
deque.AddToFront(0);
Assert.True(deque.IsSplit);
deque_str = deque.ConvertAll(_ => _ + "");
Assert.Equal(4, deque_str.Count);
Assert.Equal(new[] { "0", "1", "2", "3" }, deque_str);
}