def test_postfix_traverse(self):
tree = BinaryNode(10)
tree.right = BinaryNode(15)
tree.left = BinaryNode(5)
tree.left.left = BinaryNode(3)
tree.left.right = BinaryNode(7)
self.assertEqual(tree.postfix_traverse(), "3 7 5 15 10 ")
def _pop_operands(self, op, node_stack, operator_stack, operand_stack):
operand_node2 = node_stack.pop()
operand_node1 = node_stack.pop()
node = BinaryNode(op)
node.left = operand_node1
node.right = operand_node2
node_stack.append(node)
operand2 = operand_stack.pop()
operand1 = operand_stack.pop()
operand_stack.append(self._calc(op, operand1, operand2))
