def test_graft_doubly_links_parent_and_child(self):
parent = TreeNode(name = 'parent')
child = TreeNode(name = 'child')
parent.graft_child(child)
#assert children of parent are correct
child_ids_of_parent = [id(c) for c in parent.children]
child_ids_of_parent_spec = [id(child)]
self.assertItemsEqual(child_ids_of_parent, child_ids_of_parent_spec)
#assert parent of children is correct
self.assertEqual(id(child.parent), id(parent))
def test_trim_removes_double_link_between_parent_and_child_to_avoid_cycles(self):
parent = TreeNode(name = 'parent')
child = TreeNode(name = 'child')
parent.graft_child(child)
child.trim()
#assert child no longer in children of parent
child_ids_of_parent = [id(c) for c in parent.children]
child_ids_of_parent_spec = list()
self.assertItemsEqual(child_ids_of_parent, child_ids_of_parent_spec)
#assert parent is None for the child
self.assertIsNone(child.parent)
def test_TN_string_representation_displays_all_data_items_and_relatives_summary(self):
parent = TreeNode()
main = TreeNode(a=1, b=2)
parent.graft_child(main)
main.graft_child(TreeNode())
main.graft_child(TreeNode())
string_spec = 'TreeNode:\n'\
' parent: yes\n'\
' children: 2\n'\
' a: 1\n'\
' b: 2'
self.assertEqual(str(main), string_spec)
def test_simple_binary_tree_with_three_levels_has_4_leaves(self):
#first level
a0 = TreeNode(name='a0')
#second level
b0 = TreeNode(name='b0')
b1 = TreeNode(name='b1')
#third level
c0 = TreeNode(name='c0')
c1 = TreeNode(name='c1')
c2 = TreeNode(name='c2')
c3 = TreeNode(name='c3')
#attach everything
a0.graft_child(b0)
a0.graft_child(b1)
b0.graft_child(c0)
b0.graft_child(c1)
b1.graft_child(c2)
b1.graft_child(c3)
#confirm leaves
leaf_names = [leaf.name for leaf in a0.leaves]
leaf_names_spec = ['c0','c1','c2','c3']
self.assertItemsEqual(leaf_names, leaf_names_spec)
def test_node_self_identifies_as_not_leaf_if_any_children(self):
node = TreeNode()
node.graft_child(TreeNode())
self.assertFalse(node.is_leaf)
def test_children_is_a_sequence(self):
node = TreeNode()
node.graft_child(TreeNode())
self.assertTrue(node.children) #True, e.g. not empty list
class Traversing_A_Tree(ut.TestCase):
def setUp(self):
self.root = TreeNode(name = 'root')
self.a = TreeNode(name = 'a')
self.b = TreeNode(name = 'b')
self.c = TreeNode(name = 'c')
def test_node_generates_in_order_traversal_from_self(self):
self.root.graft_child(self.a)
self.root.graft_child(self.b)
self.b.graft_child(self.c)
names = [node.name for node in self.root.in_order_nodes]
names_spec = ['root', 'a', 'b', 'c']
self.assertSequenceEqual(names, names_spec)
def test_node_generates_post_order_traversal_from_self(self):
self.root.graft_child(self.a)
self.root.graft_child(self.b)
self.b.graft_child(self.c)
names = [node.name for node in self.root.post_order_nodes]
names_spec = ['c', 'b', 'a', 'root']
self.assertSequenceEqual(names, names_spec)
def test_node_generates_only_self_when_no_parent_or_children(self):
node_string_list_spec = ['root']
node_string_list = [node.name for node in self.root.in_order_nodes]
self.assertEqual(node_string_list_spec, node_string_list)
def test_node_generates_only_nodes_including_and_below_self_in_tree(self):
self.root.graft_child(self.a)
self.root.graft_child(self.b)
self.b.graft_child(self.c)
names = [node.name for node in self.b.in_order_nodes]
names_spec = ['b', 'c'] #i.e. 'a' is not in there
self.assertSequenceEqual(names, names_spec)
