def test_parent_read_only():
"""
Test that the parent field cannot be assigned after construction.
"""
t = Tree(None)
with pytest.raises(AttributeError):
t.parent = None
def test_data_read_only():
"""
Test that the data on a Tree cannot be assigned after construction.
"""
t = Tree(None)
with pytest.raises(AttributeError):
t.data = 0
def _copy(self) -> None:
"""
Internal method to copy the constructed Tree in memory.
"""
new_root: Tree[T] = Tree(self.root.data)
new_current = None
if self.current is self.root:
new_current = new_root
queue = [(new_root, self.root._children)]
while queue:
new_parent, children = queue.pop()
new_children = []
for child in children:
new_child: Tree[T] = Tree(child.data)
new_child._parent = new_parent
new_children.append(new_child)
queue.append((new_child, child._children))
if self.current is child:
new_current = new_child
new_parent._children = new_children
self.root = new_root
self.current = new_current
def test_minimal_tree_creation():
"""
Test creating the minimal tree using the constructor.
"""
t = Tree(None)
assert t.data is None
assert t.parent is None
assert len(t) == 0
def create_root(self, data: T) -> None:
"""
Creates the root of the tree. This is the first step in Tree building.
This should be called when a TreeBuilder is first created.
Args:
data: The optional data to put on the root node.
"""
self.root = Tree(data)
self.current = self.root
def add_child(self, data, move=False):
"""
Adds a child to the current cursor location's node.
Children indices are directly related to the order of their creation.
Args:
data: The data to put on the created child.
move: Flag to indicate if the cursor should move to this child.
Raises:
ValueError: If the TreeBuilder's root has not been initialized.
"""
self._assert_initialization_status()
self._copy_if_necessary()
child = Tree()
child._data = data
child._parent = self.current
self.current._children.append(child)
if move:
l = len(self.current)
self.move_to_child(l - 1)