diff options
Diffstat (limited to 'Lib/test/test_unparse.py')
| -rw-r--r-- | Lib/test/test_unparse.py | 38 |
1 files changed, 37 insertions, 1 deletions
diff --git a/Lib/test/test_unparse.py b/Lib/test/test_unparse.py index e38b335..f999ae8 100644 --- a/Lib/test/test_unparse.py +++ b/Lib/test/test_unparse.py @@ -130,7 +130,43 @@ docstring_prefixes = ( class ASTTestCase(unittest.TestCase): def assertASTEqual(self, ast1, ast2): - self.assertEqual(ast.dump(ast1), ast.dump(ast2)) + # Ensure the comparisons start at an AST node + self.assertIsInstance(ast1, ast.AST) + self.assertIsInstance(ast2, ast.AST) + + # An AST comparison routine modeled after ast.dump(), but + # instead of string building, it traverses the two trees + # in lock-step. + def traverse_compare(a, b, missing=object()): + if type(a) is not type(b): + self.fail(f"{type(a)!r} is not {type(b)!r}") + if isinstance(a, ast.AST): + for field in a._fields: + value1 = getattr(a, field, missing) + value2 = getattr(b, field, missing) + # Singletons are equal by definition, so further + # testing can be skipped. + if value1 is not value2: + traverse_compare(value1, value2) + elif isinstance(a, list): + try: + for node1, node2 in zip(a, b, strict=True): + traverse_compare(node1, node2) + except ValueError: + # Attempt a "pretty" error ala assertSequenceEqual() + len1 = len(a) + len2 = len(b) + if len1 > len2: + what = "First" + diff = len1 - len2 + else: + what = "Second" + diff = len2 - len1 + msg = f"{what} list contains {diff} additional elements." + raise self.failureException(msg) from None + elif a != b: + self.fail(f"{a!r} != {b!r}") + traverse_compare(ast1, ast2) def check_ast_roundtrip(self, code1, **kwargs): with self.subTest(code1=code1, ast_parse_kwargs=kwargs): |