test_144_binary_tree_preorder_traversal.rb

# frozen_string_literal: true

require_relative '../test_helper'
require_relative '../../lib/common/binary_tree'
require_relative '../../lib/easy/144_binary_tree_preorder_traversal'
require 'minitest/autorun'

class BinaryTreePreorderTraversalTest < ::Minitest::Test
  def test_default_one
    assert_equal(
      [1, 2, 3],
      preorder_traversal(
        ::TreeNode.build_tree(
          [1, nil, 2, 3]
        )
      )
    )
  end

  def test_default_two
    assert_equal(
      [],
      preorder_traversal(nil)
    )
  end

  def test_default_three
    assert_equal(
      [1],
      preorder_traversal(
        ::TreeNode.build_tree(
          [1]
        )
      )
    )
  end
end