def test_undefined_rule(self):
        tree = rule_grammar.parse('boy = howdy\n')
        assert_raises(UndefinedLabel, RuleVisitor().visit, tree)
Make sure we throw the right exception on undefined rules.
dataset/ETHPy150Open erikrose/parsimonious/parsimonious/tests/test_grammar.py/RuleVisitorTests.test_undefined_rule