Binary Tree Starter Kit

binary_tree_test.rb

require 'minitest'
require 'minitest/autorun'
require 'minitest/pride'

require './binarytree'
require './node'

class NodeTest < Minitest::Test
  def test_it_exists
    node = Node.new(99)

    assert_instance_of Node, node
  end

  def test_it_has_a_value
    node = Node.new(99)

    assert_equal 99, node.data
  end

  def test_it_has_a_next_attribute_set_to_nil
    node = Node.new(99)

    assert_nil node.left
    assert_nil node.right
  end
end

class BinaryTreeTest < Minitest::Test
  def test_it_exists
    tree = BinaryTree.new

    assert_instance_of BinaryTree, tree
  end

  def test_it_has_a_root_node_set_to_nil
    tree = BinaryTree.new

    assert_nil tree.root
  end

  def test_it_can_insert_a_node
    tree = BinaryTree.new

    tree.insert(23)

    refute_nil tree.root
    assert_equal 23, tree.root.data
  end

  def test_it_can_insert_several_nodes_in_the_right_order
    tree = BinaryTree.new

    tree.insert(61)
    tree.insert(16)
    tree.insert(92)
    tree.insert(50)

    refute_nil tree.root
    assert_equal 61, tree.root.data
    assert_equal 16, tree.root.left.data
    assert_equal 92, tree.root.right.data
    assert_equal 50, tree.root.left.right.data
  end
end

binarytree.rb

class BinaryTree
  attr_reader :root

  def initialize
    @root = nil
  end

  def insert(value)
    @root = insert_node(@root, value)
  end

  private

  def insert_node(root, value)
    # your code goes here
  end
end

node.rb

class Node
  attr_reader :data
  attr_accessor :left, :right

  def initialize(payload)
    @data = payload
    @left = nil
    @right = nil
  end
end