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"""
Tests to make sure the newobject object (which defines Python 2-compatible
``__unicode__`` and ``next`` methods) is working.
"""
from __future__ import absolute_import, division
from future import utils
from future.builtins import object, str, next, int, super
from future.utils import implements_iterator, python_2_unicode_compatible
from future.tests.base import unittest, expectedFailurePY2
class TestNewObject(unittest.TestCase):
def test_object_implements_py2_unicode_method(self):
my_unicode_str = u'Unicode string: \u5b54\u5b50'
class A(object):
def __str__(self):
return my_unicode_str
a = A()
self.assertEqual(len(str(a)), 18)
if utils.PY2:
self.assertTrue(hasattr(a, '__unicode__'))
else:
self.assertFalse(hasattr(a, '__unicode__'))
self.assertEqual(str(a), my_unicode_str)
self.assertTrue(isinstance(str(a).encode('utf-8'), bytes))
if utils.PY2:
self.assertTrue(type(unicode(a)) == unicode)
self.assertEqual(unicode(a), my_unicode_str)
# Manual equivalent on Py2 without the decorator:
if not utils.PY3:
class B(object):
def __unicode__(self):
return u'Unicode string: \u5b54\u5b50'
def __str__(self):
return unicode(self).encode('utf-8')
b = B()
assert str(a) == str(b)
def test_implements_py2_iterator(self):
class Upper(object):
def __init__(self, iterable):
self._iter = iter(iterable)
def __next__(self): # note the Py3 interface
return next(self._iter).upper()
def __iter__(self):
return self
self.assertEqual(list(Upper('hello')), list('HELLO'))
# Try combining it with the next() function:
class MyIter(object):
def __next__(self):
return 'Next!'
def __iter__(self):
return self
itr = MyIter()
self.assertEqual(next(itr), 'Next!')
itr2 = MyIter()
for i, item in enumerate(itr2):
if i >= 10:
break
self.assertEqual(item, 'Next!')
def test_implements_py2_nonzero(self):
class EvenIsTrue(object):
"""
An integer that evaluates to True if even.
"""
def __init__(self, my_int):
self.my_int = my_int
def __bool__(self):
return self.my_int % 2 == 0
def __add__(self, other):
return type(self)(self.my_int + other)
k = EvenIsTrue(5)
self.assertFalse(k)
self.assertFalse(bool(k))
self.assertTrue(k + 1)
self.assertTrue(bool(k + 1))
self.assertFalse(k + 2)
def test_int_implements_py2_nonzero(self):
"""
Tests whether the newint object provides a __nonzero__ method that
maps to __bool__ in case the user redefines __bool__ in a subclass of
newint.
"""
class EvenIsTrue(int):
"""
An integer that evaluates to True if even.
"""
def __bool__(self):
return self % 2 == 0
def __add__(self, other):
val = super().__add__(other)
return type(self)(val)
k = EvenIsTrue(5)
self.assertFalse(k)
self.assertFalse(bool(k))
self.assertTrue(k + 1)
self.assertTrue(bool(k + 1))
self.assertFalse(k + 2)
def test_non_iterator(self):
"""
The default behaviour of next(o) for a newobject o should be to raise a
TypeError, as with the corresponding builtin object.
"""
o = object()
with self.assertRaises(TypeError):
next(o)
def test_bool_empty_object(self):
"""
The default result of bool(newobject()) should be True, as with builtin
objects.
"""
o = object()
self.assertTrue(bool(o))
class MyClass(object):
pass
obj = MyClass()
self.assertTrue(bool(obj))
def test_isinstance_object_subclass(self):
"""
This was failing before
"""
class A(object):
pass
a = A()
class B(object):
pass
b = B()
self.assertFalse(isinstance(a, B))
self.assertFalse(isinstance(b, A))
self.assertTrue(isinstance(a, A))
self.assertTrue(isinstance(b, B))
class C(A):
pass
c = C()
self.assertTrue(isinstance(c, A))
self.assertFalse(isinstance(c, B))
self.assertFalse(isinstance(a, C))
self.assertFalse(isinstance(b, C))
self.assertTrue(isinstance(c, C))
@expectedFailurePY2
def test_types_isinstance_newobject(self):
a = list()
b = dict()
c = set()
self.assertTrue(isinstance(a, object))
self.assertTrue(isinstance(b, object))
self.assertTrue(isinstance(c, object))
# Old-style class instances on Py2 should still report as an instance
# of object as usual on Py2:
class D:
pass
d = D()
self.assertTrue(isinstance(d, object))
e = object()
self.assertTrue(isinstance(e, object))
class F(object):
pass
f = F()
self.assertTrue(isinstance(f, object))
class G(F):
pass
g = G()
self.assertTrue(isinstance(g, object))
class H():
pass
h = H()
self.assertTrue(isinstance(h, object))
def test_long_special_method(self):
class A(object):
def __int__(self):
return 0
a = A()
self.assertEqual(int(a), 0)
if utils.PY2:
self.assertEqual(long(a), 0)
def test_multiple_inheritance(self):
"""
Issue #96
"""
if utils.PY2:
from collections import Container
else:
from collections.abc import Container
class Base(object):
pass
class Foo(Base, Container):
def __contains__(self, item):
return False
def test_with_metaclass_and_object(self):
"""
Issue #91
"""
from future.utils import with_metaclass
class MetaClass(type):
pass
class TestClass(with_metaclass(MetaClass, object)):
pass
def test_bool(self):
"""
Issue #211
"""
from builtins import object
class ResultSet(object):
def __len__(self):
return 0
self.assertTrue(bool(ResultSet()) is False)
class ResultSet(object):
def __len__(self):
return 2
self.assertTrue(bool(ResultSet()) is True)
def test_bool2(self):
"""
If __bool__ is defined, the presence or absence of __len__ should
be irrelevant.
"""
from builtins import object
class TrueThing(object):
def __bool__(self):
return True
def __len__(self):
raise RuntimeError('__len__ should not be called')
self.assertTrue(bool(TrueThing()))
class FalseThing(object):
def __bool__(self):
return False
def __len__(self):
raise RuntimeError('__len__ should not be called')
self.assertFalse(bool(FalseThing()))
def test_cannot_assign_new_attributes_to_object(self):
"""
New attributes cannot be assigned to object() instances in Python.
The same should apply to newobject.
"""
from builtins import object
with self.assertRaises(AttributeError):
object().arbitrary_attribute_name = True
if __name__ == '__main__':
unittest.main()
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