# Test case for property # more tests are in test_descr import sys import unittest from test import support class PropertyBase(Exception): pass class PropertyGet(PropertyBase): pass class PropertySet(PropertyBase): pass class PropertyDel(PropertyBase): pass class BaseClass(object): def __init__(self): self._spam = 5 @property def spam(self): """BaseClass.getter""" return self._spam @spam.setter def spam(self, value): self._spam = value @spam.deleter def spam(self): del self._spam class SubClass(BaseClass): @BaseClass.spam.getter def spam(self): """SubClass.getter""" raise PropertyGet(self._spam) @spam.setter def spam(self, value): raise PropertySet(self._spam) @spam.deleter def spam(self): raise PropertyDel(self._spam) class PropertyDocBase(object): _spam = 1 def _get_spam(self): return self._spam spam = property(_get_spam, doc="spam spam spam") class PropertyDocSub(PropertyDocBase): @PropertyDocBase.spam.getter def spam(self): """The decorator does not use this doc string""" return self._spam class PropertySubNewGetter(BaseClass): @BaseClass.spam.getter def spam(self): """new docstring""" return 5 class PropertyNewGetter(object): @property def spam(self): """original docstring""" return 1 @spam.getter def spam(self): """new docstring""" return 8 class PropertyTests(unittest.TestCase): def test_property_decorator_baseclass(self): # see #1620 base = BaseClass() self.assertEqual(base.spam, 5) self.assertEqual(base._spam, 5) base.spam = 10 self.assertEqual(base.spam, 10) self.assertEqual(base._spam, 10) delattr(base, "spam") self.assertTrue(not hasattr(base, "spam")) self.assertTrue(not hasattr(base, "_spam")) base.spam = 20 self.assertEqual(base.spam, 20) self.assertEqual(base._spam, 20) def test_property_decorator_subclass(self): # see #1620 sub = SubClass() self.assertRaises(PropertyGet, getattr, sub, "spam") self.assertRaises(PropertySet, setattr, sub, "spam", None) self.assertRaises(PropertyDel, delattr, sub, "spam") @unittest.skipIf(sys.flags.optimize >= 2, "Docstrings are omitted with -O2 and above") def test_property_decorator_subclass_doc(self): sub = SubClass() self.assertEqual(sub.__class__.spam.__doc__, "SubClass.getter") @unittest.skipIf(sys.flags.optimize >= 2, "Docstrings are omitted with -O2 and above") def test_property_decorator_baseclass_doc(self): base = BaseClass() self.assertEqual(base.__class__.spam.__doc__, "BaseClass.getter") def test_property_decorator_doc(self): base = PropertyDocBase() sub = PropertyDocSub() self.assertEqual(base.__class__.spam.__doc__, "spam spam spam") self.assertEqual(sub.__class__.spam.__doc__, "spam spam spam") @unittest.skipIf(sys.flags.optimize >= 2, "Docstrings are omitted with -O2 and above") def test_property_getter_doc_override(self): newgettersub = PropertySubNewGetter() self.assertEqual(newgettersub.spam, 5) self.assertEqual(newgettersub.__class__.spam.__doc__, "new docstring") newgetter = PropertyNewGetter() self.assertEqual(newgetter.spam, 8) self.assertEqual(newgetter.__class__.spam.__doc__, "new docstring") def test_property___isabstractmethod__descriptor(self): for val in (True, False, [], [1], '', '1'): class C(object): def foo(self): pass foo.__isabstractmethod__ = val foo = property(foo) self.assertIs(C.foo.__isabstractmethod__, bool(val)) # check that the property's __isabstractmethod__ descriptor does the # right thing when presented with a value that fails truth testing: class NotBool(object): def __bool__(self): raise ValueError() __len__ = __bool__ with self.assertRaises(ValueError): class C(object): def foo(self): pass foo.__isabstractmethod__ = NotBool() foo = property(foo) C.foo.__isabstractmethod__ @unittest.skipIf(sys.flags.optimize >= 2, "Docstrings are omitted with -O2 and above") def test_property_builtin_doc_writable(self): p = property(doc='basic') self.assertEqual(p.__doc__, 'basic') p.__doc__ = 'extended' self.assertEqual(p.__doc__, 'extended') @unittest.skipIf(sys.flags.optimize >= 2, "Docstrings are omitted with -O2 and above") def test_property_decorator_doc_writable(self): class PropertyWritableDoc(object): @property def spam(self): """Eggs""" return "eggs" sub = PropertyWritableDoc() self.assertEqual(sub.__class__.spam.__doc__, 'Eggs') sub.__class__.spam.__doc__ = 'Spam' self.assertEqual(sub.__class__.spam.__doc__, 'Spam') @support.refcount_test def test_refleaks_in___init__(self): gettotalrefcount = support.get_attribute(sys, 'gettotalrefcount') fake_prop = property('fget', 'fset', 'fdel', 'doc') refs_before = gettotalrefcount() for i in range(100): fake_prop.__init__('fget', 'fset', 'fdel', 'doc') self.assertAlmostEqual(gettotalrefcount() - refs_before, 0, delta=10) @unittest.skipIf(sys.flags.optimize >= 2, "Docstrings are omitted with -O2 and above") def test_class_property(self): class A: @classmethod @property def __doc__(cls): return 'A doc for %r' % cls.__name__ self.assertEqual(A.__doc__, "A doc for 'A'") @unittest.skipIf(sys.flags.optimize >= 2, "Docstrings are omitted with -O2 and above") def test_class_property_override(self): class A: """First""" @classmethod @property def __doc__(cls): return 'Second' self.assertEqual(A.__doc__, 'Second') def test_property_set_name_incorrect_args(self): p = property() for i in (0, 1, 3): with self.assertRaisesRegex( TypeError, fr'^__set_name__\(\) takes 2 positional arguments but {i} were given$' ): p.__set_name__(*([0] * i)) def test_property_setname_on_property_subclass(self): # https://github.com/python/cpython/issues/100942 # Copy was setting the name field without first # verifying that the copy was an actual property # instance. As a result, the code below was # causing a segfault. class pro(property): def __new__(typ, *args, **kwargs): return "abcdef" class A: pass p = property.__new__(pro) p.__set_name__(A, 1) np = p.getter(lambda self: 1) # Issue 5890: subclasses of property do not preserve method __doc__ strings class PropertySub(property): """This is a subclass of property""" class PropertySubWoDoc(property): pass class PropertySubSlots(property): """This is a subclass of property that defines __slots__""" __slots__ = () class PropertySubclassTests(unittest.TestCase): def test_slots_docstring_copy_exception(self): try: class Foo(object): @PropertySubSlots def spam(self): """Trying to copy this docstring will raise an exception""" return 1 except AttributeError: pass else: raise Exception("AttributeError not raised") @unittest.skipIf(sys.flags.optimize >= 2, "Docstrings are omitted with -O2 and above") def test_issue41287(self): self.assertEqual(PropertySub.__doc__, "This is a subclass of property", "Docstring of `property` subclass is ignored") doc = PropertySub(None, None, None, "issue 41287 is fixed").__doc__ self.assertEqual(doc, "issue 41287 is fixed", "Subclasses of `property` ignores `doc` constructor argument") def getter(x): """Getter docstring""" def getter_wo_doc(x): pass for ps in property, PropertySub, PropertySubWoDoc: doc = ps(getter, None, None, "issue 41287 is fixed").__doc__ self.assertEqual(doc, "issue 41287 is fixed", "Getter overrides explicit property docstring (%s)" % ps.__name__) doc = ps(getter, None, None, None).__doc__ self.assertEqual(doc, "Getter docstring", "Getter docstring is not picked-up (%s)" % ps.__name__) doc = ps(getter_wo_doc, None, None, "issue 41287 is fixed").__doc__ self.assertEqual(doc, "issue 41287 is fixed", "Getter overrides explicit property docstring (%s)" % ps.__name__) doc = ps(getter_wo_doc, None, None, None).__doc__ self.assertIsNone(doc, "Property class doc appears in instance __doc__ (%s)" % ps.__name__) @unittest.skipIf(sys.flags.optimize >= 2, "Docstrings are omitted with -O2 and above") def test_docstring_copy(self): class Foo(object): @PropertySub def spam(self): """spam wrapped in property subclass""" return 1 self.assertEqual( Foo.spam.__doc__, "spam wrapped in property subclass") @unittest.skipIf(sys.flags.optimize >= 2, "Docstrings are omitted with -O2 and above") def test_docstring_copy2(self): """ Property tries to provide the best docstring it finds for its instances. If a user-provided docstring is available, it is preserved on copies. If no docstring is available during property creation, the property will utilize the docstring from the getter if available. """ def getter1(self): return 1 def getter2(self): """doc 2""" return 2 def getter3(self): """doc 3""" return 3 # Case-1: user-provided doc is preserved in copies # of property with undocumented getter p = property(getter1, None, None, "doc-A") p2 = p.getter(getter2) self.assertEqual(p.__doc__, "doc-A") self.assertEqual(p2.__doc__, "doc-A") # Case-2: user-provided doc is preserved in copies # of property with documented getter p = property(getter2, None, None, "doc-A") p2 = p.getter(getter3) self.assertEqual(p.__doc__, "doc-A") self.assertEqual(p2.__doc__, "doc-A") # Case-3: with no user-provided doc new getter doc # takes precendence p = property(getter2, None, None, None) p2 = p.getter(getter3) self.assertEqual(p.__doc__, "doc 2") self.assertEqual(p2.__doc__, "doc 3") # Case-4: A user-provided doc is assigned after property construction # with documented getter. The doc IS NOT preserved. # It's an odd behaviour, but it's a strange enough # use case with no easy solution. p = property(getter2, None, None, None) p.__doc__ = "user" p2 = p.getter(getter3) self.assertEqual(p.__doc__, "user") self.assertEqual(p2.__doc__, "doc 3") # Case-5: A user-provided doc is assigned after property construction # with UNdocumented getter. The doc IS preserved. p = property(getter1, None, None, None) p.__doc__ = "user" p2 = p.getter(getter2) self.assertEqual(p.__doc__, "user") self.assertEqual(p2.__doc__, "user") @unittest.skipIf(sys.flags.optimize >= 2, "Docstrings are omitted with -O2 and above") def test_property_setter_copies_getter_docstring(self): class Foo(object): def __init__(self): self._spam = 1 @PropertySub def spam(self): """spam wrapped in property subclass""" return self._spam @spam.setter def spam(self, value): """this docstring is ignored""" self._spam = value foo = Foo() self.assertEqual(foo.spam, 1) foo.spam = 2 self.assertEqual(foo.spam, 2) self.assertEqual( Foo.spam.__doc__, "spam wrapped in property subclass") class FooSub(Foo): @Foo.spam.setter def spam(self, value): """another ignored docstring""" self._spam = 'eggs' foosub = FooSub() self.assertEqual(foosub.spam, 1) foosub.spam = 7 self.assertEqual(foosub.spam, 'eggs') self.assertEqual( FooSub.spam.__doc__, "spam wrapped in property subclass") @unittest.skipIf(sys.flags.optimize >= 2, "Docstrings are omitted with -O2 and above") def test_property_new_getter_new_docstring(self): class Foo(object): @PropertySub def spam(self): """a docstring""" return 1 @spam.getter def spam(self): """a new docstring""" return 2 self.assertEqual(Foo.spam.__doc__, "a new docstring") class FooBase(object): @PropertySub def spam(self): """a docstring""" return 1 class Foo2(FooBase): @FooBase.spam.getter def spam(self): """a new docstring""" return 2 self.assertEqual(Foo.spam.__doc__, "a new docstring") class _PropertyUnreachableAttribute: msg_format = None obj = None cls = None def _format_exc_msg(self, msg): return self.msg_format.format(msg) @classmethod def setUpClass(cls): cls.obj = cls.cls() def test_get_property(self): with self.assertRaisesRegex(AttributeError, self._format_exc_msg("has no getter")): self.obj.foo def test_set_property(self): with self.assertRaisesRegex(AttributeError, self._format_exc_msg("has no setter")): self.obj.foo = None def test_del_property(self): with self.assertRaisesRegex(AttributeError, self._format_exc_msg("has no deleter")): del self.obj.foo class PropertyUnreachableAttributeWithName(_PropertyUnreachableAttribute, unittest.TestCase): msg_format = r"^property 'foo' of 'PropertyUnreachableAttributeWithName\.cls' object {}$" class cls: foo = property() class PropertyUnreachableAttributeNoName(_PropertyUnreachableAttribute, unittest.TestCase): msg_format = r"^property of 'PropertyUnreachableAttributeNoName\.cls' object {}$" class cls: pass cls.foo = property() if __name__ == '__main__': unittest.main()