cpython/Lib/test/test_funcattrs.py

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import textwrap
import types
import typing
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import unittest
import warnings
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def global_function():
def inner_function():
class LocalClass:
pass
global inner_global_function
def inner_global_function():
def inner_function2():
pass
return inner_function2
return LocalClass
return lambda: inner_function
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class FuncAttrsTest(unittest.TestCase):
def setUp(self):
class F:
def a(self):
pass
def b():
return 3
self.fi = F()
self.F = F
self.b = b
def cannot_set_attr(self, obj, name, value, exceptions):
try:
setattr(obj, name, value)
except exceptions:
pass
else:
self.fail("shouldn't be able to set %s to %r" % (name, value))
try:
delattr(obj, name)
except exceptions:
pass
else:
self.fail("shouldn't be able to del %s" % name)
class FunctionPropertiesTest(FuncAttrsTest):
# Include the external setUp method that is common to all tests
def test_module(self):
self.assertEqual(self.b.__module__, __name__)
def test_dir_includes_correct_attrs(self):
self.b.known_attr = 7
self.assertIn('known_attr', dir(self.b),
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"set attributes not in dir listing of method")
# Test on underlying function object of method
self.F.a.known_attr = 7
self.assertIn('known_attr', dir(self.fi.a), "set attribute on function "
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"implementations, should show up in next dir")
def test_duplicate_function_equality(self):
# Body of `duplicate' is the exact same as self.b
def duplicate():
'my docstring'
return 3
self.assertNotEqual(self.b, duplicate)
def test_copying___code__(self):
def test(): pass
self.assertEqual(test(), None)
test.__code__ = self.b.__code__
self.assertEqual(test(), 3) # self.b always returns 3, arbitrarily
def test_invalid___code___assignment(self):
def A(): pass
def B(): yield
async def C(): yield
async def D(x): await x
for src in [A, B, C, D]:
for dst in [A, B, C, D]:
if src == dst:
continue
assert src.__code__.co_flags != dst.__code__.co_flags
prev = dst.__code__
try:
with self.assertWarnsRegex(DeprecationWarning, 'code object of non-matching type'):
dst.__code__ = src.__code__
finally:
with warnings.catch_warnings():
warnings.filterwarnings('ignore', '', DeprecationWarning)
dst.__code__ = prev
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def test___globals__(self):
self.assertIs(self.b.__globals__, globals())
self.cannot_set_attr(self.b, '__globals__', 2,
(AttributeError, TypeError))
def test___builtins__(self):
self.assertIs(self.b.__builtins__, __builtins__)
self.cannot_set_attr(self.b, '__builtins__', 2,
(AttributeError, TypeError))
# bpo-42990: If globals is specified and has no "__builtins__" key,
# a function inherits the current builtins namespace.
def func(s): return len(s)
ns = {}
func2 = type(func)(func.__code__, ns)
self.assertIs(func2.__globals__, ns)
self.assertIs(func2.__builtins__, __builtins__)
# Make sure that the function actually works.
self.assertEqual(func2("abc"), 3)
self.assertEqual(ns, {})
# Define functions using exec() with different builtins,
# and test inheritance when globals has no "__builtins__" key
code = textwrap.dedent("""
def func3(s): pass
func4 = type(func3)(func3.__code__, {})
""")
safe_builtins = {'None': None}
ns = {'type': type, '__builtins__': safe_builtins}
exec(code, ns)
self.assertIs(ns['func3'].__builtins__, safe_builtins)
self.assertIs(ns['func4'].__builtins__, safe_builtins)
self.assertIs(ns['func3'].__globals__['__builtins__'], safe_builtins)
self.assertNotIn('__builtins__', ns['func4'].__globals__)
def test___closure__(self):
a = 12
def f(): print(a)
c = f.__closure__
self.assertIsInstance(c, tuple)
self.assertEqual(len(c), 1)
# don't have a type object handy
self.assertEqual(c[0].__class__.__name__, "cell")
self.cannot_set_attr(f, "__closure__", c, AttributeError)
def test_cell_new(self):
cell_obj = types.CellType(1)
self.assertEqual(cell_obj.cell_contents, 1)
cell_obj = types.CellType()
msg = "shouldn't be able to read an empty cell"
with self.assertRaises(ValueError, msg=msg):
cell_obj.cell_contents
def test_empty_cell(self):
def f(): print(a)
try:
f.__closure__[0].cell_contents
except ValueError:
pass
else:
self.fail("shouldn't be able to read an empty cell")
a = 12
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def test_set_cell(self):
a = 12
def f(): return a
c = f.__closure__
c[0].cell_contents = 9
self.assertEqual(c[0].cell_contents, 9)
self.assertEqual(f(), 9)
self.assertEqual(a, 9)
del c[0].cell_contents
try:
c[0].cell_contents
except ValueError:
pass
else:
self.fail("shouldn't be able to read an empty cell")
with self.assertRaises(NameError):
f()
with self.assertRaises(UnboundLocalError):
print(a)
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def test___name__(self):
self.assertEqual(self.b.__name__, 'b')
self.b.__name__ = 'c'
self.assertEqual(self.b.__name__, 'c')
self.b.__name__ = 'd'
self.assertEqual(self.b.__name__, 'd')
# __name__ and __name__ must be a string
self.cannot_set_attr(self.b, '__name__', 7, TypeError)
# __name__ must be available when in restricted mode. Exec will raise
# AttributeError if __name__ is not available on f.
s = """def f(): pass\nf.__name__"""
exec(s, {'__builtins__': {}})
# Test on methods, too
self.assertEqual(self.fi.a.__name__, 'a')
self.cannot_set_attr(self.fi.a, "__name__", 'a', AttributeError)
def test___qualname__(self):
# PEP 3155
self.assertEqual(self.b.__qualname__, 'FuncAttrsTest.setUp.<locals>.b')
self.assertEqual(FuncAttrsTest.setUp.__qualname__, 'FuncAttrsTest.setUp')
self.assertEqual(global_function.__qualname__, 'global_function')
self.assertEqual(global_function().__qualname__,
'global_function.<locals>.<lambda>')
self.assertEqual(global_function()().__qualname__,
'global_function.<locals>.inner_function')
self.assertEqual(global_function()()().__qualname__,
'global_function.<locals>.inner_function.<locals>.LocalClass')
self.assertEqual(inner_global_function.__qualname__, 'inner_global_function')
self.assertEqual(inner_global_function().__qualname__, 'inner_global_function.<locals>.inner_function2')
self.b.__qualname__ = 'c'
self.assertEqual(self.b.__qualname__, 'c')
self.b.__qualname__ = 'd'
self.assertEqual(self.b.__qualname__, 'd')
# __qualname__ must be a string
self.cannot_set_attr(self.b, '__qualname__', 7, TypeError)
def test___type_params__(self):
def generic[T](): pass
def not_generic(): pass
lambda_ = lambda: ...
T, = generic.__type_params__
self.assertIsInstance(T, typing.TypeVar)
self.assertEqual(generic.__type_params__, (T,))
for func in (not_generic, lambda_):
with self.subTest(func=func):
self.assertEqual(func.__type_params__, ())
with self.assertRaises(TypeError):
del func.__type_params__
with self.assertRaises(TypeError):
func.__type_params__ = 42
func.__type_params__ = (T,)
self.assertEqual(func.__type_params__, (T,))
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def test___code__(self):
num_one, num_two = 7, 8
def a(): pass
def b(): return 12
def c(): return num_one
def d(): return num_two
def e(): return num_one, num_two
for func in [a, b, c, d, e]:
self.assertEqual(type(func.__code__), types.CodeType)
self.assertEqual(c(), 7)
self.assertEqual(d(), 8)
d.__code__ = c.__code__
self.assertEqual(c.__code__, d.__code__)
self.assertEqual(c(), 7)
# self.assertEqual(d(), 7)
try:
b.__code__ = c.__code__
except ValueError:
pass
else:
self.fail("__code__ with different numbers of free vars should "
"not be possible")
try:
e.__code__ = d.__code__
except ValueError:
pass
else:
self.fail("__code__ with different numbers of free vars should "
"not be possible")
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def test_blank_func_defaults(self):
self.assertEqual(self.b.__defaults__, None)
del self.b.__defaults__
self.assertEqual(self.b.__defaults__, None)
def test_func_default_args(self):
def first_func(a, b):
return a+b
def second_func(a=1, b=2):
return a+b
self.assertEqual(first_func.__defaults__, None)
self.assertEqual(second_func.__defaults__, (1, 2))
first_func.__defaults__ = (1, 2)
self.assertEqual(first_func.__defaults__, (1, 2))
self.assertEqual(first_func(), 3)
self.assertEqual(first_func(3), 5)
self.assertEqual(first_func(3, 5), 8)
del second_func.__defaults__
self.assertEqual(second_func.__defaults__, None)
try:
second_func()
except TypeError:
pass
else:
self.fail("__defaults__ does not update; deleting it does not "
"remove requirement")
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class InstancemethodAttrTest(FuncAttrsTest):
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def test___class__(self):
self.assertEqual(self.fi.a.__self__.__class__, self.F)
self.cannot_set_attr(self.fi.a, "__class__", self.F, TypeError)
def test___func__(self):
self.assertEqual(self.fi.a.__func__, self.F.a)
self.cannot_set_attr(self.fi.a, "__func__", self.F.a, AttributeError)
def test___self__(self):
self.assertEqual(self.fi.a.__self__, self.fi)
self.cannot_set_attr(self.fi.a, "__self__", self.fi, AttributeError)
def test___func___non_method(self):
# Behavior should be the same when a method is added via an attr
# assignment
self.fi.id = types.MethodType(id, self.fi)
self.assertEqual(self.fi.id(), id(self.fi))
# Test usage
try:
self.fi.id.unknown_attr
except AttributeError:
pass
else:
self.fail("using unknown attributes should raise AttributeError")
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# Test assignment and deletion
self.cannot_set_attr(self.fi.id, 'unknown_attr', 2, AttributeError)
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class ArbitraryFunctionAttrTest(FuncAttrsTest):
def test_set_attr(self):
self.b.known_attr = 7
self.assertEqual(self.b.known_attr, 7)
try:
self.fi.a.known_attr = 7
except AttributeError:
pass
else:
self.fail("setting attributes on methods should raise error")
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def test_delete_unknown_attr(self):
try:
del self.b.unknown_attr
except AttributeError:
pass
else:
self.fail("deleting unknown attribute should raise TypeError")
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def test_unset_attr(self):
for func in [self.b, self.fi.a]:
try:
func.non_existent_attr
except AttributeError:
pass
else:
self.fail("using unknown attributes should raise "
"AttributeError")
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class FunctionDictsTest(FuncAttrsTest):
def test_setting_dict_to_invalid(self):
self.cannot_set_attr(self.b, '__dict__', None, TypeError)
from collections import UserDict
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d = UserDict({'known_attr': 7})
self.cannot_set_attr(self.fi.a.__func__, '__dict__', d, TypeError)
def test_setting_dict_to_valid(self):
d = {'known_attr': 7}
self.b.__dict__ = d
# Test assignment
self.assertIs(d, self.b.__dict__)
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# ... and on all the different ways of referencing the method's func
self.F.a.__dict__ = d
self.assertIs(d, self.fi.a.__func__.__dict__)
self.assertIs(d, self.fi.a.__dict__)
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# Test value
self.assertEqual(self.b.known_attr, 7)
self.assertEqual(self.b.__dict__['known_attr'], 7)
# ... and again, on all the different method's names
self.assertEqual(self.fi.a.__func__.known_attr, 7)
self.assertEqual(self.fi.a.known_attr, 7)
def test_delete___dict__(self):
try:
del self.b.__dict__
except TypeError:
pass
else:
self.fail("deleting function dictionary should raise TypeError")
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def test_unassigned_dict(self):
self.assertEqual(self.b.__dict__, {})
def test_func_as_dict_key(self):
value = "Some string"
d = {}
d[self.b] = value
self.assertEqual(d[self.b], value)
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class FunctionDocstringTest(FuncAttrsTest):
def test_set_docstring_attr(self):
self.assertEqual(self.b.__doc__, None)
docstr = "A test method that does nothing"
self.b.__doc__ = docstr
self.F.a.__doc__ = docstr
self.assertEqual(self.b.__doc__, docstr)
self.assertEqual(self.fi.a.__doc__, docstr)
self.cannot_set_attr(self.fi.a, "__doc__", docstr, AttributeError)
def test_delete_docstring(self):
self.b.__doc__ = "The docstring"
del self.b.__doc__
self.assertEqual(self.b.__doc__, None)
def cell(value):
"""Create a cell containing the given value."""
def f():
print(a)
a = value
return f.__closure__[0]
def empty_cell(empty=True):
"""Create an empty cell."""
def f():
print(a)
# the intent of the following line is simply "if False:"; it's
# spelt this way to avoid the danger that a future optimization
# might simply remove an "if False:" code block.
if not empty:
a = 1729
return f.__closure__[0]
class CellTest(unittest.TestCase):
def test_comparison(self):
# These tests are here simply to exercise the comparison code;
# their presence should not be interpreted as providing any
# guarantees about the semantics (or even existence) of cell
# comparisons in future versions of CPython.
self.assertTrue(cell(2) < cell(3))
self.assertTrue(empty_cell() < cell('saturday'))
self.assertTrue(empty_cell() == empty_cell())
self.assertTrue(cell(-36) == cell(-36.0))
self.assertTrue(cell(True) > empty_cell())
class StaticMethodAttrsTest(unittest.TestCase):
def test_func_attribute(self):
def f():
pass
c = classmethod(f)
self.assertTrue(c.__func__ is f)
s = staticmethod(f)
self.assertTrue(s.__func__ is f)
class BuiltinFunctionPropertiesTest(unittest.TestCase):
# XXX Not sure where this should really go since I can't find a
# test module specifically for builtin_function_or_method.
def test_builtin__qualname__(self):
import time
# builtin function:
self.assertEqual(len.__qualname__, 'len')
self.assertEqual(time.time.__qualname__, 'time')
# builtin classmethod:
self.assertEqual(dict.fromkeys.__qualname__, 'dict.fromkeys')
self.assertEqual(float.__getformat__.__qualname__,
'float.__getformat__')
# builtin staticmethod:
self.assertEqual(str.maketrans.__qualname__, 'str.maketrans')
self.assertEqual(bytes.maketrans.__qualname__, 'bytes.maketrans')
# builtin bound instance method:
self.assertEqual([1, 2, 3].append.__qualname__, 'list.append')
self.assertEqual({'foo': 'bar'}.pop.__qualname__, 'dict.pop')
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if __name__ == "__main__":
unittest.main()