"""Tests for the unparse.py script in the Tools/parser directory.""" import unittest import test.support import pathlib import random import tokenize import ast def read_pyfile(filename): """Read and return the contents of a Python source file (as a string), taking into account the file encoding.""" with tokenize.open(filename) as stream: return stream.read() for_else = """\ def f(): for x in range(10): break else: y = 2 z = 3 """ while_else = """\ def g(): while True: break else: y = 2 z = 3 """ relative_import = """\ from . import fred from .. import barney from .australia import shrimp as prawns """ nonlocal_ex = """\ def f(): x = 1 def g(): nonlocal x x = 2 y = 7 def h(): nonlocal x, y """ # also acts as test for 'except ... as ...' raise_from = """\ try: 1 / 0 except ZeroDivisionError as e: raise ArithmeticError from e """ class_decorator = """\ @f1(arg) @f2 class Foo: pass """ elif1 = """\ if cond1: suite1 elif cond2: suite2 else: suite3 """ elif2 = """\ if cond1: suite1 elif cond2: suite2 """ try_except_finally = """\ try: suite1 except ex1: suite2 except ex2: suite3 else: suite4 finally: suite5 """ with_simple = """\ with f(): suite1 """ with_as = """\ with f() as x: suite1 """ with_two_items = """\ with f() as x, g() as y: suite1 """ docstring_prefixes = [ "", "class foo():\n ", "def foo():\n ", "async def foo():\n ", ] class ASTTestCase(unittest.TestCase): def assertASTEqual(self, ast1, ast2): self.assertEqual(ast.dump(ast1), ast.dump(ast2)) def check_ast_roundtrip(self, code1, **kwargs): ast1 = ast.parse(code1, **kwargs) code2 = ast.unparse(ast1) ast2 = ast.parse(code2, **kwargs) self.assertASTEqual(ast1, ast2) def check_invalid(self, node, raises=ValueError): self.assertRaises(raises, ast.unparse, node) def get_source(self, code1, code2=None, strip=True): code2 = code2 or code1 code1 = ast.unparse(ast.parse(code1)) if strip: code1 = code1.strip() return code1, code2 def check_src_roundtrip(self, code1, code2=None, strip=True): code1, code2 = self.get_source(code1, code2, strip) self.assertEqual(code2, code1) def check_src_dont_roundtrip(self, code1, code2=None, strip=True): code1, code2 = self.get_source(code1, code2, strip) self.assertNotEqual(code2, code1) class UnparseTestCase(ASTTestCase): # Tests for specific bugs found in earlier versions of unparse def test_fstrings(self): # See issue 25180 self.check_ast_roundtrip(r"""f'{f"{0}"*3}'""") self.check_ast_roundtrip(r"""f'{f"{y}"*3}'""") def test_strings(self): self.check_ast_roundtrip("u'foo'") self.check_ast_roundtrip("r'foo'") self.check_ast_roundtrip("b'foo'") def test_del_statement(self): self.check_ast_roundtrip("del x, y, z") def test_shifts(self): self.check_ast_roundtrip("45 << 2") self.check_ast_roundtrip("13 >> 7") def test_for_else(self): self.check_ast_roundtrip(for_else) def test_while_else(self): self.check_ast_roundtrip(while_else) def test_unary_parens(self): self.check_ast_roundtrip("(-1)**7") self.check_ast_roundtrip("(-1.)**8") self.check_ast_roundtrip("(-1j)**6") self.check_ast_roundtrip("not True or False") self.check_ast_roundtrip("True or not False") def test_integer_parens(self): self.check_ast_roundtrip("3 .__abs__()") def test_huge_float(self): self.check_ast_roundtrip("1e1000") self.check_ast_roundtrip("-1e1000") self.check_ast_roundtrip("1e1000j") self.check_ast_roundtrip("-1e1000j") def test_min_int(self): self.check_ast_roundtrip(str(-(2 ** 31))) self.check_ast_roundtrip(str(-(2 ** 63))) def test_imaginary_literals(self): self.check_ast_roundtrip("7j") self.check_ast_roundtrip("-7j") self.check_ast_roundtrip("0j") self.check_ast_roundtrip("-0j") def test_lambda_parentheses(self): self.check_ast_roundtrip("(lambda: int)()") def test_chained_comparisons(self): self.check_ast_roundtrip("1 < 4 <= 5") self.check_ast_roundtrip("a is b is c is not d") def test_function_arguments(self): self.check_ast_roundtrip("def f(): pass") self.check_ast_roundtrip("def f(a): pass") self.check_ast_roundtrip("def f(b = 2): pass") self.check_ast_roundtrip("def f(a, b): pass") self.check_ast_roundtrip("def f(a, b = 2): pass") self.check_ast_roundtrip("def f(a = 5, b = 2): pass") self.check_ast_roundtrip("def f(*, a = 1, b = 2): pass") self.check_ast_roundtrip("def f(*, a = 1, b): pass") self.check_ast_roundtrip("def f(*, a, b = 2): pass") self.check_ast_roundtrip("def f(a, b = None, *, c, **kwds): pass") self.check_ast_roundtrip("def f(a=2, *args, c=5, d, **kwds): pass") self.check_ast_roundtrip("def f(*args, **kwargs): pass") def test_relative_import(self): self.check_ast_roundtrip(relative_import) def test_nonlocal(self): self.check_ast_roundtrip(nonlocal_ex) def test_raise_from(self): self.check_ast_roundtrip(raise_from) def test_bytes(self): self.check_ast_roundtrip("b'123'") def test_annotations(self): self.check_ast_roundtrip("def f(a : int): pass") self.check_ast_roundtrip("def f(a: int = 5): pass") self.check_ast_roundtrip("def f(*args: [int]): pass") self.check_ast_roundtrip("def f(**kwargs: dict): pass") self.check_ast_roundtrip("def f() -> None: pass") def test_set_literal(self): self.check_ast_roundtrip("{'a', 'b', 'c'}") def test_set_comprehension(self): self.check_ast_roundtrip("{x for x in range(5)}") def test_dict_comprehension(self): self.check_ast_roundtrip("{x: x*x for x in range(10)}") def test_class_decorators(self): self.check_ast_roundtrip(class_decorator) def test_class_definition(self): self.check_ast_roundtrip("class A(metaclass=type, *[], **{}): pass") def test_elifs(self): self.check_ast_roundtrip(elif1) self.check_ast_roundtrip(elif2) def test_try_except_finally(self): self.check_ast_roundtrip(try_except_finally) def test_starred_assignment(self): self.check_ast_roundtrip("a, *b, c = seq") self.check_ast_roundtrip("a, (*b, c) = seq") self.check_ast_roundtrip("a, *b[0], c = seq") self.check_ast_roundtrip("a, *(b, c) = seq") def test_with_simple(self): self.check_ast_roundtrip(with_simple) def test_with_as(self): self.check_ast_roundtrip(with_as) def test_with_two_items(self): self.check_ast_roundtrip(with_two_items) def test_dict_unpacking_in_dict(self): # See issue 26489 self.check_ast_roundtrip(r"""{**{'y': 2}, 'x': 1}""") self.check_ast_roundtrip(r"""{**{'y': 2}, **{'x': 1}}""") def test_ext_slices(self): self.check_ast_roundtrip("a[i]") self.check_ast_roundtrip("a[i,]") self.check_ast_roundtrip("a[i, j]") self.check_ast_roundtrip("a[()]") self.check_ast_roundtrip("a[i:j]") self.check_ast_roundtrip("a[:j]") self.check_ast_roundtrip("a[i:]") self.check_ast_roundtrip("a[i:j:k]") self.check_ast_roundtrip("a[:j:k]") self.check_ast_roundtrip("a[i::k]") self.check_ast_roundtrip("a[i:j,]") self.check_ast_roundtrip("a[i:j, k]") def test_invalid_raise(self): self.check_invalid(ast.Raise(exc=None, cause=ast.Name(id="X"))) def test_invalid_fstring_constant(self): self.check_invalid(ast.JoinedStr(values=[ast.Constant(value=100)])) def test_invalid_fstring_conversion(self): self.check_invalid( ast.FormattedValue( value=ast.Constant(value="a", kind=None), conversion=ord("Y"), # random character format_spec=None, ) ) def test_invalid_set(self): self.check_invalid(ast.Set(elts=[])) def test_invalid_yield_from(self): self.check_invalid(ast.YieldFrom(value=None)) def test_docstrings(self): docstrings = ( 'this ends with double quote"', 'this includes a """triple quote"""' ) for docstring in docstrings: # check as Module docstrings for easy testing self.check_ast_roundtrip(f"'{docstring}'") def test_constant_tuples(self): self.check_src_roundtrip(ast.Constant(value=(1,), kind=None), "(1,)") self.check_src_roundtrip( ast.Constant(value=(1, 2, 3), kind=None), "(1, 2, 3)" ) @test.support.skip_if_new_parser("Pegen does not support type annotation yet") def test_function_type(self): for function_type in ( "() -> int", "(int, int) -> int", "(Callable[complex], More[Complex(call.to_typevar())]) -> None" ): self.check_ast_roundtrip(function_type, mode="func_type") class CosmeticTestCase(ASTTestCase): """Test if there are cosmetic issues caused by unnecesary additions""" def test_simple_expressions_parens(self): self.check_src_roundtrip("(a := b)") self.check_src_roundtrip("await x") self.check_src_roundtrip("x if x else y") self.check_src_roundtrip("lambda x: x") self.check_src_roundtrip("1 + 1") self.check_src_roundtrip("1 + 2 / 3") self.check_src_roundtrip("(1 + 2) / 3") self.check_src_roundtrip("(1 + 2) * 3 + 4 * (5 + 2)") self.check_src_roundtrip("(1 + 2) * 3 + 4 * (5 + 2) ** 2") self.check_src_roundtrip("~ x") self.check_src_roundtrip("x and y") self.check_src_roundtrip("x and y and z") self.check_src_roundtrip("x and (y and x)") self.check_src_roundtrip("(x and y) and z") self.check_src_roundtrip("(x ** y) ** z ** q") self.check_src_roundtrip("x >> y") self.check_src_roundtrip("x << y") self.check_src_roundtrip("x >> y and x >> z") self.check_src_roundtrip("x + y - z * q ^ t ** k") self.check_src_roundtrip("P * V if P and V else n * R * T") self.check_src_roundtrip("lambda P, V, n: P * V == n * R * T") self.check_src_roundtrip("flag & (other | foo)") self.check_src_roundtrip("not x == y") self.check_src_roundtrip("x == (not y)") self.check_src_roundtrip("yield x") self.check_src_roundtrip("yield from x") self.check_src_roundtrip("call((yield x))") self.check_src_roundtrip("return x + (yield x)") def test_docstrings(self): docstrings = ( '"""simple doc string"""', '''"""A more complex one with some newlines"""''', '''"""Foo bar baz empty newline"""''', '"""With some \t"""', '"""Foo "bar" baz """', ) for prefix in docstring_prefixes: for docstring in docstrings: self.check_src_roundtrip(f"{prefix}{docstring}") def test_docstrings_negative_cases(self): # Test some cases that involve strings in the children of the # first node but aren't docstrings to make sure we don't have # False positives. docstrings_negative = ( 'a = """false"""', '"""false""" + """unless its optimized"""', '1 + 1\n"""false"""', 'f"""no, top level but f-fstring"""' ) for prefix in docstring_prefixes: for negative in docstrings_negative: # this cases should be result with single quote # rather then triple quoted docstring src = f"{prefix}{negative}" self.check_ast_roundtrip(src) self.check_src_dont_roundtrip(src) class DirectoryTestCase(ASTTestCase): """Test roundtrip behaviour on all files in Lib and Lib/test.""" lib_dir = pathlib.Path(__file__).parent / ".." test_directories = (lib_dir, lib_dir / "test") skip_files = {"test_fstring.py"} run_always_files = {"test_grammar.py", "test_syntax.py", "test_compile.py", "test_ast.py", "test_asdl_parser.py"} _files_to_test = None @classmethod def files_to_test(cls): if cls._files_to_test is not None: return cls._files_to_test items = [ item.resolve() for directory in cls.test_directories for item in directory.glob("*.py") if not item.name.startswith("bad") ] # Test limited subset of files unless the 'cpu' resource is specified. if not test.support.is_resource_enabled("cpu"): tests_to_run_always = {item for item in items if item.name in cls.run_always_files} items = set(random.sample(items, 10)) # Make sure that at least tests that heavily use grammar features are # always considered in order to reduce the chance of missing something. items = list(items | tests_to_run_always) # bpo-31174: Store the names sample to always test the same files. # It prevents false alarms when hunting reference leaks. cls._files_to_test = items return items def test_files(self): for item in self.files_to_test(): if test.support.verbose: print(f"Testing {item.absolute()}") # Some f-strings are not correctly round-tripped by # Tools/parser/unparse.py. See issue 28002 for details. # We need to skip files that contain such f-strings. if item.name in self.skip_files: if test.support.verbose: print(f"Skipping {item.absolute()}: see issue 28002") continue with self.subTest(filename=item): source = read_pyfile(item) self.check_ast_roundtrip(source) if __name__ == "__main__": unittest.main()