view Lib/test/test_dynamicclassattribute.py @ 87690:66c1c9f32567 default tip

Add use_weakref option to functools.lru_cache The use_weakref option makes lru_cache create weak references to the function arguments when creating the cache key, which prevents them from staying in the memory forever even after all other references to them are gone. This is a proof of concept for http://bugs.python.org/issue19859
author Radomir Dopieralski <devel@sheep.art.pl>
date Tue, 03 Dec 2013 16:02:48 +0100
parents 3752c94368dd
children
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# Test case for DynamicClassAttribute
# more tests are in test_descr

import abc
import sys
import unittest
from test.support import run_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 __nonzero__(self):
                raise ValueError()
            __len__ = __nonzero__
        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")



def test_main():
    run_unittest(PropertyTests, PropertySubclassTests)

if __name__ == '__main__':
    test_main()