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#!/usr/bin/python
#
# This tests the property decorator in kaa.utils, which is designed to be
# forward-compatible with Python 2.6 and Python 3.0. Demonstrates propety
# getters, setters, and deleters, with inheritance.
#
# See:
# http://bugs.python.org/issue1416
# http://permalink.gmane.org/gmane.comp.python.general/551183
# http://bugs.python.org/issue1620
from kaa.utils import property
class A(object):
def __init__(self):
self._readonly = 42
self._writable = 0
@property
def readonly(self):
"readonly docstring"
return self._readonly
@property
def writable(self):
return self._writable
@writable.setter
def writable(self, value):
self._writable = value
class B(A):
@A.readonly.getter
def readonly(self):
"subclass readonly docstring"
return super(B, self).readonly * 2
@readonly.setter
def readonly(self, value):
# Ok, not exactly readonly anymore :)
self._readonly = value
@A.writable.deleter
def writable(self):
self._writable = None
a = A()
assert(a.readonly == 42)
try:
a.readonly = 0
except AttributeError:
pass
else:
raise AttributeError('a.readonly was writable')
a.writable = a.readonly / 2
assert(a.writable == 21)
try:
del a.writable
except AttributeError:
pass
else:
raise AttributeError('del a.writable did not raise exception as expected')
assert(A.readonly.__doc__ == 'readonly docstring')
b = B()
assert(b.readonly == 42*2)
b.readonly = 20
assert(b.readonly == 20*2)
del b.writable
assert(b.writable is None)
assert(B.readonly.__doc__ == 'subclass readonly docstring')
print 'All property tests ok.'
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