old_contents: # _*_ encoding: utf-8 _*_
  """Tests for binary search tree."""
  from bst import BST
  import pytest
  
  
  @pytest.fixture
  def empty_instance():
      """Empty root fixture."""
      root = BST()
      return root
  
  
  @pytest.fixture
  def instance():
      """Full tree fixture."""
      root = BST()
      for n in range(20):
          root.insert(n)
      return root
  
  
      def test_new_root(instance):
          """Test that our root is a root."""
          assert isinstance(instance, BST)
  
new_contents: # _*_ encoding: utf-8 _*_
  """Tests for binary search tree."""
  from bst import BST
  import pytest
  
  
  @pytest.fixture
  def empty_instance():
      """Empty root fixture."""
      root = BST()
      return root
  
  
  @pytest.fixture
  def instance():
      """Full tree fixture."""
      root = BST()
      for n in range(20):
          root.insert(n)
      return root
  
  
      def test_new_tree(instance):
          """Test that our tree is a tree."""
          assert isinstance(instance, BST)
  
  
      def test_new_empty_tree(empty_instance):
          """Test that an empty tree is still a tree."""
          assert all
          ([
              test.empty_instance.date is None,
              test.empty_instance.root is None,
              test.empty_instance.left is None,
              test.empty_instance.right is None
          ])
  
  
      def test_insert_many(empty_instance):
          """Test insert method with many values."""
          insertions = list(range(10))
          for root in insertions:
              test.empty_instance.insert(root)
          for root in insertions:
              assert test.empty_instance.contains(root)
  
  
      def test_contains_false(instance):
          """Test false example for contains method."""
          assert not instance.contains(1000)
  
subject: test insert many, empty tree, and contains false.