def test_attach_attaches_subtrees_as_left_and_right_children_of_Position(
self):
lt = LinkedBinaryTree()
lt._root = lt._Node('foo', None, None, None)
lt._root._left = lt._Node('bar', None, None, None)
lt._size = 2
branch_left = LinkedBinaryTree()
branch_left._root = branch_left._Node('spam', None, None)
branch_left._size = 1
branch_right = LinkedBinaryTree()
branch_right._root = branch_right._Node('eggs', None, None)
branch_right._size = 1
attach_position = lt.Position(lt, lt._root._left)
lt._attach(attach_position, branch_left, branch_right)
self.assertEqual(lt._size, 4)
self.assertIs(attach_position._node._left._element, 'spam')
self.assertIs(attach_position._node._right._element, 'eggs')
self.assertIs(attach_position._node._left._parent,
attach_position._node)
self.assertIs(attach_position._node._right._parent,
attach_position._node)
self.assertEqual(branch_left._size, 0)
self.assertEqual(branch_right._size, 0)
def test_TreeABC_is_empty_returns_correct_boolean_values(self):
lt_empty = LinkedBinaryTree()
lt_non_empty = LinkedBinaryTree()
lt_non_empty._root = lt_non_empty._Node('foo', None, None, None)
lt_non_empty._size = 1
self.assertTrue(lt_empty.is_empty())
self.assertFalse(lt_non_empty.is_empty())
def test_add_right_raises_ValueError_with_nonempty_node(self):
lt = LinkedBinaryTree()
lt._root = lt._Node('foo', None, None, None)
lt._root._right = lt._Node('bar', lt._root, None, None)
lt._size = 2
root_position = lt.Position(lt, lt._root)
self.assertRaises(ValueError, lt._add_right, root_position, 'foo')
def test_validate_raises_ValueError_with_deprecated_node(self):
lt = LinkedBinaryTree()
lt._root = lt._Node('foo')
lt._root._left = lt._Node('bar', None, None, None)
lt._root._left._parent = lt._root._left # deprecate node
lt._size = 2
bad_position = lt.Position(lt, lt._root._left)
self.assertRaises(ValueError, lt._validate, bad_position)
def test_parent_returns_none_if_position_is_root(self):
lt = LinkedBinaryTree()
lt._root = lt._Node('foo')
lt._size = 1
root_position = lt.Position(lt, lt._root)
result = lt.parent(root_position)
self.assertIsNone(result)
def test_right_returns_none_if_position_has_no_right_child(self):
lt = LinkedBinaryTree()
lt._root = lt._Node('foo')
lt._size = 1
root_position = lt.Position(lt, lt._root)
result = lt.right(root_position)
self.assertIsNone(result)
def test_TreeABC_is_leaf_returns_correct_boolean_values(self):
lt = LinkedBinaryTree()
lt._root = lt._Node('foo', None, None, None)
lt._root._left = lt._Node('bar', lt._root, None, None)
lt._size = 2
root_position = lt.Position(lt, lt._root)
non_root_position = lt.Position(lt, lt._root._left)
self.assertTrue(lt.is_leaf(non_root_position))
self.assertFalse(lt.is_leaf(root_position))
def test_num_children_returns_number_of_children_nodes_of_position(self):
lt = LinkedBinaryTree()
lt._root = lt._Node('foo')
lt._size = 1
expected_result = 0
root_position = lt.Position(lt, lt._root)
result = lt.num_children(root_position)
self.assertEqual(result, expected_result)
lt._root._left = lt._Node('bar', lt._root, None, None)
lt._root._right = lt._Node('baz', lt._root, None, None)
lt._size = 3
expected_result = 2
result = lt.num_children(root_position)
self.assertEqual(result, expected_result)
def test_delete_raises_ValueError_when_called_on_Position_with_two_children(
self):
lt = LinkedBinaryTree()
lt._root = lt._Node('foo', None, None, None)
lt._root._left = lt._Node('bar', lt._root, None, None)
lt._root._left._left = lt._Node('baz', lt._root._left, None, None)
lt._root._left._right = lt._Node('spam', lt._root._left, None, None)
lt._size = 4
pos_to_delete = lt.Position(lt, lt._root._left)
self.assertRaises(ValueError, lt._delete, pos_to_delete)
def test_BinaryTreeABC_sibling_returns_None_on_position_with_no_sibling(
self):
lt = LinkedBinaryTree()
lt._root = lt._Node('foo', None, None, None)
lt._root._left = lt._Node('bar', None, None, None)
lt._size = 2
only_child_position = lt.Position(lt, lt._root._left)
result_position = lt.sibling(only_child_position)
self.assertIsNone(result_position)
def test_root_returns_the_root_position_of_the_tree(self):
lt = LinkedBinaryTree()
expected_element = 'foo'
n = lt._Node(expected_element, None, None, None)
lt._root = n
lt._size = 1
result = lt.root()
self.assertIsNotNone(result)
self.assertIs(result._node._element, expected_element)
def test_parent_returns_position_parent_when_position_not_root(self):
lt = LinkedBinaryTree()
lt._root = lt._Node('foo')
lt._root._left = lt._Node('bar', lt._root, None, None)
lt._size = 2
child_position = lt.Position(lt, lt._root._left)
expected_result = lt.Position(lt, lt._root)
result = lt.parent(child_position)
self.assertEqual(result, expected_result)
def test_right_returns_position_of_right_child(self):
lt = LinkedBinaryTree()
lt._root = lt._Node('foo')
lt._root._right = lt._Node('bar', lt._root, None, None)
lt._size = 2
root_position = lt.Position(lt, lt._root)
expected_result = lt.Position(lt, lt._root._right)
result = lt.right(root_position)
self.assertEqual(result, expected_result)
def test_add_right_stores_element_as_right_child_returns_Position(self):
lt = LinkedBinaryTree()
lt._root = lt._Node('foo', None, None, None)
lt._size = 1
root_position = lt.Position(lt, lt._root)
expected_element = 'bar'
result_position = lt._add_right(root_position, expected_element)
self.assertIsInstance(result_position, lt.Position)
self.assertIs(result_position._node._element, expected_element)
self.assertIs(root_position._node._right._element, expected_element)
def test_TreeABC_depth_returns_number_of_levels_from_Position_to_root(
self):
lt = LinkedBinaryTree()
lt._root = lt._Node('foo', None, None, None)
lt._root._left = lt._Node('bar', lt._root, None, None)
lt._root._left._left = lt._Node('baz', lt._root._left, None, None)
lt._size = 3
expected_result = 2
position = lt.Position(lt, lt._root._left._left)
result = lt.depth(position)
self.assertEqual(result, expected_result)
def test_replace_replaces_element_at_Position_returns_old_element(self):
lt = LinkedBinaryTree()
old_element = 'bar'
new_element = 'baz'
lt._root = lt._Node('foo', None, None, None)
lt._root._left = lt._Node(old_element, lt._root, None, None)
lt._size = 2
pos_to_replace = lt.Position(lt, lt._root._left)
result_element = lt._replace(pos_to_replace, new_element)
self.assertIs(pos_to_replace._node._element, new_element)
self.assertIs(result_element, old_element)
def test_attach_raises_TypeError_when_different_tree_types_provided(self):
lt = LinkedBinaryTree()
lt._root = lt._Node('foo', None, None, None)
lt._root._left = lt._Node('bar', None, None, None)
lt._size = 2
lt_left = BinaryTree()
lt_right = Tree()
attach_position = lt.Position(lt, lt._root._left)
self.assertRaises(TypeError, lt._attach, attach_position, lt_left,
lt_right)
def test_TreeABC_height_returns_height_of_subtree_at_Position(self):
lt = LinkedBinaryTree()
lt._root = lt._Node('foo', None, None, None)
lt._root._left = lt._Node('bar', lt._root, None, None)
lt._root._left._left = lt._Node('baz', lt._root._left, None, None)
lt._root._left._left._right = lt._Node('spam', lt._root._left._left,
None, None)
lt._size = 4
expected_result = 3
position = lt.Position(lt, lt._root)
result = lt._height(position)
self.assertEqual(result, expected_result)
def test_BinaryTreeABC_sibling_returns_other_sibling_Position(self):
lt = LinkedBinaryTree()
lt._root = lt._Node('foo', None, None, None)
lt._root._left = lt._Node('bar', lt._root, None, None)
lt._root._right = lt._Node('baz', lt._root, None, None)
lt._size = 3
left_child_position = lt.Position(lt, lt._root._left)
right_child_position = lt.Position(lt, lt._root._right)
lefts_sibling_position = lt.sibling(left_child_position)
rights_sibling_position = lt.sibling(right_child_position)
self.assertEqual(lefts_sibling_position, right_child_position)
self.assertEqual(rights_sibling_position, left_child_position)
def test_attach_raises_ValueError_when_Position_not_a_leaf(self):
lt = LinkedBinaryTree()
lt._root = lt._Node('foo', None, None, None)
lt._root._left = lt._Node('bar', None, None, None)
lt._root._right = lt._Node('baz', None, None, None)
lt._size = 3
lt_left = LinkedBinaryTree()
lt_right = LinkedBinaryTree()
invalid_position = lt.Position(lt, lt._root)
self.assertRaises(ValueError, lt._attach, invalid_position, lt_left,
lt_right)
def test_len_returns_the_number_of_elements_in_tree(self):
lt = LinkedBinaryTree()
expected_result = 0
result = len(lt)
self.assertEqual(result, expected_result)
lt._size = 1
expected_result = 1
result = len(lt)
self.assertEqual(result, expected_result)
def test_BinaryTreeABC_children_returns_iteration_of_Position_children(
self):
lt = LinkedBinaryTree()
lt._root = lt._Node('foo', None, None, None)
lt._root._left = lt._Node('bar', lt._root, None, None)
lt._root._right = lt._Node('baz', lt._root, None, None)
lt._size = 3
parent_position = lt.Position(lt, lt._root)
children_generator = lt.children(parent_position)
first_result = next(children_generator)
second_result = next(children_generator)
self.assertEqual(first_result, lt.Position(lt, lt._root._left))
self.assertEqual(second_result, lt.Position(lt, lt._root._right))
self.assertRaises(StopIteration, children_generator.__next__)
def test_delete_deletes_node_on_Position_replaces_with_a_single_child(
self):
lt = LinkedBinaryTree()
element_to_delete = 'bar'
child_element = 'baz'
lt._root = lt._Node('foo', None, None, None)
lt._root._left = lt._Node(element_to_delete, lt._root, None, None)
lt._root._left._left = lt._Node(child_element, lt._root._left, None,
None)
lt._size = 3
pos_to_delete = lt.Position(lt, lt._root._left)
deleted_element = lt._delete(pos_to_delete)
self.assertIs(deleted_element, element_to_delete)
self.assertIs(lt._root._left._element, child_element)
self.assertIs(lt._root._left._parent, lt._root)
def test_TreeABC_preorder_generates_a_correct_iteration_of_Positions(self):
# Composing the following tree:
# r
# rl rr
# rll rlr rrl rrr
lc = LinkedBinaryTree()
lc._root = lc._Node('r', None, None, None)
lc._root._left = lc._Node('rl', lc._root, None, None)
lc._root._right = lc._Node('rr', lc._root, None, None)
lc._root._left._left = lc._Node('rll', lc._root._left, None, None)
lc._root._left._right = lc._Node('rlr', lc._root._left, None, None)
lc._root._right._left = lc._Node('rrl', lc._root._right, None, None)
lc._root._right._right = lc._Node('rrr', lc._root._right, None, None)
lc._size = 7
expected_element_order = ['r', 'rl', 'rll', 'rlr', 'rr', 'rrl', 'rrr']
result_positions = [p for p in lc.preorder()]
result_elements = [p._node._element for p in result_positions]
for p in result_positions:
self.assertIsInstance(p, lc.Position)
self.assertEqual(expected_element_order, result_elements)
def test_add_root_raises_ValueError_with_nonempty_tree(self):
lt = LinkedBinaryTree()
lt._root = lt._Node('foo', None, None, None)
lt._size = 1
self.assertRaises(ValueError, lt._add_root, 'foo')