cpython/Lib/test/test_gc.py

122 lines
2.1 KiB
Python

import gc
def test_list():
l = []
l.append(l)
gc.collect()
del l
assert gc.collect() == 1
def test_dict():
d = {}
d[1] = d
gc.collect()
del d
assert gc.collect() == 1
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
assert gc.collect() == 2
def test_class():
class A:
pass
A.a = A
gc.collect()
del A
assert gc.collect() > 0
def test_instance():
class A:
pass
a = A()
a.a = a
gc.collect()
del a
assert gc.collect() > 0
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
assert gc.collect() > 0
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()
gc.garbage[:] = []
del a
del b
assert gc.collect() > 0
assert id(gc.garbage[0]) == id_a
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
assert gc.collect() == 2
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():
enabled = gc.isenabled()
gc.disable()
assert not gc.isenabled()
test_list()
test_dict()
test_tuple()
test_class()
test_instance()
test_method()
test_finalizer()
test_function()
test_del()
# test gc.enable() even if GC is disabled by default
gc.enable()
assert gc.isenabled()
if not enabled:
gc.disable()
test_all()