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import unittest
from pegen.grammar import Grammar
from pegen.grammar_parser import GeneratedParser as GrammarParser
from pegen.utils import parse_string
from pegen.validator import SubRuleValidator, ValidationError
class TestPegen(unittest.TestCase):
def test_rule_with_no_collision(self) -> None:
grammar_source = """
start: bad_rule
sum:
| NAME '-' NAME
| NAME '+' NAME
"""
grammar: Grammar = parse_string(grammar_source, GrammarParser)
validator = SubRuleValidator(grammar)
for rule_name, rule in grammar.rules.items():
validator.validate_rule(rule_name, rule)
def test_rule_with_simple_collision(self) -> None:
grammar_source = """
start: bad_rule
sum:
| NAME '+' NAME
| NAME '+' NAME ';'
"""
grammar: Grammar = parse_string(grammar_source, GrammarParser)
validator = SubRuleValidator(grammar)
with self.assertRaises(ValidationError):
for rule_name, rule in grammar.rules.items():
validator.validate_rule(rule_name, rule)
def test_rule_with_collision_after_some_other_rules(self) -> None:
grammar_source = """
start: bad_rule
sum:
| NAME '+' NAME
| NAME '*' NAME ';'
| NAME '-' NAME
| NAME '+' NAME ';'
"""
grammar: Grammar = parse_string(grammar_source, GrammarParser)
validator = SubRuleValidator(grammar)
with self.assertRaises(ValidationError):
for rule_name, rule in grammar.rules.items():
validator.validate_rule(rule_name, rule)
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