private void ConstructBaseTestTree()
{
_root = new BinaryTreeNode <int>(7);
_node4 = new BinaryTreeNode <int>(4);
_node5 = new BinaryTreeNode <int>(5);
_node8 = new BinaryTreeNode <int>(8);
_node15 = new BinaryTreeNode <int>(15);
_node20 = new BinaryTreeNode <int>(20);
_root.LeftChild = _node4;
_root.RightChild = _node15;
_node15.LeftChild = _node8;
_node15.RightChild = _node20;
_node4.RightChild = _node5;
_sutRoot = new BinaryTreeNode <int>(7);
_sutNode4 = new BinaryTreeNode <int>(4);
_sutNode15 = new BinaryTreeNode <int>(15);
_sutNode8 = new BinaryTreeNode <int>(8);
_sutNode5 = new BinaryTreeNode <int>(5);
_sutNode20 = new BinaryTreeNode <int>(20);
_tree = new BinarySearchTree <int>(_sutRoot);
_tree.AddNodes(_sutNode4, _sutNode5, _sutNode8, _sutNode15, _sutNode20);
_sutRoot.LeftChild = _sutNode4;
_sutRoot.RightChild = _sutNode15;
_sutNode15.LeftChild = _sutNode8;
_sutNode15.RightChild = _sutNode20;
_sutNode4.RightChild = _sutNode5;
}