def test_nodes_at_level(self):
tree = BinaryDecisionTree(n_features=1)
split = BinaryDecisionTreeSplit(feature_id=0, value=0.0)
tree.split_node(0, split)
tree.split_node(2, split)
print(tree)
self.assertEqual([0], tree.nodes_at_level(1))
self.assertEqual([1, 2], tree.nodes_at_level(2))
self.assertEqual([5, 6], tree.nodes_at_level(3))
self.assertEqual([], tree.nodes_at_level(4))
