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# test __delattr__ and __setattr__
# feature test for __setattr__/__delattr__
try:
class Test():
def __delattr__(self, attr): pass
del Test().noexist
except AttributeError:
print('SKIP')
raise SystemExit
# this class just prints the calls to see if they were executed
class A():
def __getattr__(self, attr):
print('get', attr)
return 1
def __setattr__(self, attr, val):
print('set', attr, val)
def __delattr__(self, attr):
print('del', attr)
a = A()
# check basic behaviour
print(getattr(a, 'foo'))
setattr(a, 'bar', 2)
delattr(a, 'baz')
# check meta behaviour
getattr(a, '__getattr__') # should not call A.__getattr__
getattr(a, '__setattr__') # should not call A.__getattr__
getattr(a, '__delattr__') # should not call A.__getattr__
setattr(a, '__setattr__', 1) # should call A.__setattr__
delattr(a, '__delattr__') # should call A.__delattr__
# this class acts like a dictionary
class B:
def __init__(self, d):
# store the dict in the class, not instance, so
# we don't get infinite recursion in __getattr_
B.d = d
def __getattr__(self, attr):
if attr in B.d:
return B.d[attr]
else:
raise AttributeError(attr)
def __setattr__(self, attr, value):
B.d[attr] = value
def __delattr__(self, attr):
del B.d[attr]
a = B({"a":1, "b":2})
print(a.a, a.b)
a.a = 3
print(a.a, a.b)
del a.a
try:
print(a.a)
except AttributeError:
print("AttributeError")
# test object.__setattr__
class C:
def __init__(self):
pass
def __setattr__(self, attr, value):
print(attr, "=", value)
def __delattr__(self, attr):
print("del", attr)
c = C()
c.a = 5
try:
print(c.a)
except AttributeError:
print("AttributeError")
object.__setattr__(c, "a", 5)
super(C, c).__setattr__("b", 6)
print(c.a)
print(c.b)
try:
# attribute name must be string
object.__setattr__(c, 5, 5)
except TypeError:
print("TypeError")
# test object.__delattr__
del c.a
print(c.a)
object.__delattr__(c, "a")
try:
print(c.a)
except AttributeError:
print("AttributeError")
super(C, c).__delattr__("b")
try:
print(c.b)
except AttributeError:
print("AttributeError")
try:
object.__delattr__(c, "c")
except AttributeError:
print("AttributeError")
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