public void MaxTest()
{
//Arrange
var bst = new BinarySearchTree<int, string>();
bst.Add(5, "A");
bst.Add(4, "B");
bst.Add(6, "C");
bst.Add(0, "D");
bst.Add(7, "E");
//Act
var testResult = bst.Max();
//Assert
Assert.AreEqual(testResult.Key, 7);
}