# Test case for DynamicClassAttribute
# more tests are in test_descr
import abc
import sys
import unittest
from types import DynamicClassAttribute
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
@DynamicClassAttribute
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):
spam = BaseClass.__dict__['spam']
@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 = DynamicClassAttribute(_get_spam, doc="spam spam spam")
class PropertyDocSub(PropertyDocBase):
spam = PropertyDocBase.__dict__['spam']
@spam.getter
def spam(self):
"""The decorator does not use this doc string"""
return self._spam
class PropertySubNewGetter(BaseClass):
spam = BaseClass.__dict__['spam']
@spam.getter
def spam(self):
"""new docstring"""
return 5
class PropertyNewGetter(object):
@DynamicClassAttribute
def spam(self):
"""original docstring"""
return 1
@spam.getter
def spam(self):
"""new docstring"""
return 8
class ClassWithAbstractVirtualProperty(metaclass=abc.ABCMeta):
@DynamicClassAttribute
@abc.abstractmethod
def color():
pass
class ClassWithPropertyAbstractVirtual(metaclass=abc.ABCMeta):
@abc.abstractmethod
@DynamicClassAttribute
def color():
pass
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__.__dict__['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__.__dict__['spam'].__doc__, "BaseClass.getter")
def test_property_decorator_doc(self):
base = PropertyDocBase()
sub = PropertyDocSub()
self.assertEqual(base.__class__.__dict__['spam'].__doc__, "spam spam spam")
self.assertEqual(sub.__class__.__dict__['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__.__dict__['spam'].__doc__, "new docstring")
newgetter = PropertyNewGetter()
self.assertEqual(newgetter.spam, 8)
self.assertEqual(newgetter.__class__.__dict__['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 = DynamicClassAttribute(foo)
self.assertIs(C.__dict__['foo'].__isabstractmethod__, bool(val))
# check that the DynamicClassAttribute'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 = DynamicClassAttribute(foo)
def test_abstract_virtual(self):
self.assertRaises(TypeError, ClassWithAbstractVirtualProperty)
self.assertRaises(TypeError, ClassWithPropertyAbstractVirtual)
class APV(ClassWithPropertyAbstractVirtual):
pass
self.assertRaises(TypeError, APV)
class AVP(ClassWithAbstractVirtualProperty):
pass
self.assertRaises(TypeError, AVP)
class Okay1(ClassWithAbstractVirtualProperty):
@DynamicClassAttribute
def color(self):
return self._color
def __init__(self):
self._color = 'cyan'
with self.assertRaises(AttributeError):
Okay1.color
self.assertEqual(Okay1().color, 'cyan')
class Okay2(ClassWithAbstractVirtualProperty):
@DynamicClassAttribute
def color(self):
return self._color
def __init__(self):
self._color = 'magenta'
with self.assertRaises(AttributeError):
Okay2.color
self.assertEqual(Okay2().color, 'magenta')
# Issue 5890: subclasses of DynamicClassAttribute do not preserve method __doc__ strings
class PropertySub(DynamicClassAttribute):
"""This is a subclass of DynamicClassAttribute"""
class PropertySubSlots(DynamicClassAttribute):
"""This is a subclass of DynamicClassAttribute that defines __slots__"""
__slots__ = ()
class PropertySubclassTests(unittest.TestCase):
@unittest.skipIf(hasattr(PropertySubSlots, '__doc__'),
"__doc__ is already present, __slots__ will have no effect")
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
print('\n',spam.__doc__)
except AttributeError:
pass
else:
raise Exception("AttributeError not raised")
@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 DynamicClassAttribute subclass"""
return 1
self.assertEqual(
Foo.__dict__['spam'].__doc__,
"spam wrapped in DynamicClassAttribute subclass")
@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 DynamicClassAttribute 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.__dict__['spam'].__doc__,
"spam wrapped in DynamicClassAttribute subclass")
class FooSub(Foo):
spam = Foo.__dict__['spam']
@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.__dict__['spam'].__doc__,
"spam wrapped in DynamicClassAttribute 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.__dict__['spam'].__doc__, "a new docstring")
class FooBase(object):
@PropertySub
def spam(self):
"""a docstring"""
return 1
class Foo2(FooBase):
spam = FooBase.__dict__['spam']
@spam.getter
def spam(self):
"""a new docstring"""
return 2
self.assertEqual(Foo.__dict__['spam'].__doc__, "a new docstring")
if __name__ == '__main__':
unittest.main()