def test_postorder(self):
a = ParseTree(
1, [ParseTree(2),
ParseTree(3, [ParseTree(4)]),
ParseTree(5)])
for i, j in zip(a.postorder(), [2, 4, 3, 5, 1]):
self.assertEqual(i, j)
def test_preorder(self):
a = ParseTree(
1, [ParseTree(2),
ParseTree(3, [ParseTree(4)]),
ParseTree(5)])
for i, j in zip(a.preorder(), [1, 2, 3, 4, 5]):
self.assertEqual(i, j)
def test_postorder_subtrees(self):
two = ParseTree(2)
four = ParseTree(4)
three = ParseTree(3, [four])
five = ParseTree(5)
one = ParseTree(1, [two, three, five])
for i, j in zip(one.postorder(values=False),
[two, four, three, five, one]):
self.assertEqual(i, j)
def test_expand_excludes_terminals(self):
tree = ParseTree(self.A)
self.assertEqual(frontier_values(tree), [self.A])
tree.expand([self.B, "hello", self.B])
self.assertEqual(frontier_values(tree), [self.B, self.B])
tree.frontier[1].expand([self.A, "world", self.A])
self.assertEqual(frontier_values(tree), [self.B, self.A, self.A])
def test_expand_propagates_to_ancestors(self):
tree = ParseTree(self.A)
self.assertEqual(frontier_values(tree), [self.A])
tree.expand([self.B, self.B])
self.assertEqual(frontier_values(tree), [self.B, self.B])
tree.frontier[1].expand([self.A, self.B, self.A])
self.assertEqual(frontier_values(tree),
[self.B, self.A, self.B, self.A])
def setUp(self):
self.A = Nonterminal("A")
self.B = Nonterminal("B")
self.t1 = ParseTree(self.A)
self.t2 = ParseTree(self.A)
self.t3 = ParseTree(self.B)
self.t4 = ParseTree(self.A, [self.t2, ParseTree("a"), self.t3])
self.t = ParseTree(self.A, [ParseTree("a"), self.t1, self.t4])
def test_string_excludes_childless_nonterminals(self):
tree = ParseTree(self.A, [])
self.assertEqual(tree.string(), "")
def test_string_traverses_tree(self):
tree = ParseTree(self.A, ["Hello", "world!"])
self.assertEqual(tree.string(), "Hello world!")
def test_expand_empty_production_shrinks_frontier(self):
tree = ParseTree(self.A)
self.assertEqual(frontier_values(tree), [self.A])
tree.expand(())
self.assertEqual(frontier_values(tree), [])
def test_isleaf(self):
a = ParseTree(5)
self.assertTrue(a.isleaf())
b = ParseTree(4, [ParseTree(6)])
self.assertFalse(b.isleaf())