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from test_support import verify, verbose, TestFailed
import gc
def run_test(name, thunk):
if verbose:
print "testing %s..." % name,
try:
thunk()
except TestFailed:
if verbose:
print "failed (expected %s but got %s)" % (result,
test_result)
raise TestFailed, name
else:
if verbose:
print "ok"
def test_list():
l = []
l.append(l)
gc.collect()
del l
if gc.collect() != 1:
raise TestFailed
def test_dict():
d = {}
d[1] = d
gc.collect()
del d
if gc.collect() != 1:
raise TestFailed
def test_tuple():
# since tuples are immutable we close the loop with a list
l = []
t = (l,)
l.append(t)
gc.collect()
del t
del l
if gc.collect() != 2:
raise TestFailed
def test_class():
class A:
pass
A.a = A
gc.collect()
del A
if gc.collect() == 0:
raise TestFailed
def test_instance():
class A:
pass
a = A()
a.a = a
gc.collect()
del a
if gc.collect() == 0:
raise TestFailed
def test_method():
# Tricky: self.__init__ is a bound method, it references the instance.
class A:
def __init__(self):
self.init = self.__init__
a = A()
gc.collect()
del a
if gc.collect() == 0:
raise TestFailed
def test_finalizer():
# A() is uncollectable if it is part of a cycle, make sure it shows up
# in gc.garbage.
class A:
def __del__(self): pass
class B:
pass
a = A()
a.a = a
id_a = id(a)
b = B()
b.b = b
gc.collect()
del a
del b
if gc.collect() == 0:
raise TestFailed
for obj in gc.garbage:
if id(obj) == id_a:
del obj.a
break
else:
raise TestFailed
gc.garbage.remove(obj)
def test_function():
# Tricky: f -> d -> f, code should call d.clear() after the exec to
# break the cycle.
d = {}
exec("def f(): pass\n") in d
gc.collect()
del d
if gc.collect() != 2:
raise TestFailed
def test_saveall():
# Verify that cyclic garbage like lists show up in gc.garbage if the
# SAVEALL option is enabled.
debug = gc.get_debug()
gc.set_debug(debug | gc.DEBUG_SAVEALL)
l = []
l.append(l)
id_l = id(l)
del l
gc.collect()
try:
for obj in gc.garbage:
if id(obj) == id_l:
del obj[:]
break
else:
raise TestFailed
gc.garbage.remove(obj)
finally:
gc.set_debug(debug)
def test_del():
# __del__ methods can trigger collection, make this to happen
thresholds = gc.get_threshold()
gc.enable()
gc.set_threshold(1)
class A:
def __del__(self):
dir(self)
a = A()
del a
gc.disable()
apply(gc.set_threshold, thresholds)
def test_all():
run_test("lists", test_list)
run_test("dicts", test_dict)
run_test("tuples", test_tuple)
run_test("classes", test_class)
run_test("instances", test_instance)
run_test("methods", test_method)
run_test("functions", test_function)
run_test("finalizers", test_finalizer)
run_test("__del__", test_del)
run_test("saveall", test_saveall)
def test():
if verbose:
print "disabling automatic collection"
enabled = gc.isenabled()
gc.disable()
verify(not gc.isenabled() )
debug = gc.get_debug()
gc.set_debug(debug & ~gc.DEBUG_LEAK) # this test is supposed to leak
try:
test_all()
finally:
gc.set_debug(debug)
# test gc.enable() even if GC is disabled by default
if verbose:
print "restoring automatic collection"
# make sure to always test gc.enable()
gc.enable()
verify(gc.isenabled())
if not enabled:
gc.disable()
test()
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