public void DeleteTest()
{
//Arrange
var bst = new BinarySearchTree<int, string>();
bst.Add(5, "A");
bst.Add(3, "B");
bst.Add(6, "C");
bst.Add(2, "D");
bst.Add(7, "E");
bst.Add(4, "F");
//Act
bst.Delete(3);
var testResult = bst.GetNodeByKey(5).LeftNode;
//Assert
Assert.AreEqual(testResult.Key, 4);
}