traverseda
/
cpython
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

Convert test_gc to use unittest.

This commit is contained in:
Collin Winter 2007-04-06 20:00:05 +00:00
parent e10deca7e0
commit fef1dcf433
1 changed files with 525 additions and 565 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

354
Lib/test/test_gc.py
View File

@ -1,39 +1,56 @@
from test.test_support import verify, verbose, TestFailed, vereq
import unittest
from test.test_support import verbose, run_unittest
import sys
import gc
import weakref
def expect(actual, expected, name):
if actual != expected:
raise TestFailed, "test_%s: actual %r, expected %r" % (
name, actual, expected)
### Support code
###############################################################################
def expect_nonzero(actual, name):
if actual == 0:
raise TestFailed, "test_%s: unexpected zero" % name
# Bug 1055820 has several tests of longstanding bugs involving weakrefs and
# cyclic gc.
def run_test(name, thunk):
if verbose:
print "testing %s..." % name,
thunk()
if verbose:
print "ok"
# An instance of C1055820 has a self-loop, so becomes cyclic trash when
# unreachable.
class C1055820(object):
def __init__(self, i):
self.i = i
self.loop = self
def test_list():
class GC_Detector(object):
# Create an instance I. Then gc hasn't happened again so long as
# I.gc_happened is false.
def __init__(self):
self.gc_happened = False
def it_happened(ignored):
self.gc_happened = True
# Create a piece of cyclic trash that triggers it_happened when
# gc collects it.
self.wr = weakref.ref(C1055820(666), it_happened)
### Tests
###############################################################################
class GCTests(unittest.TestCase):
def test_list(self):
l = []
l.append(l)
gc.collect()
del l
expect(gc.collect(), 1, "list")
self.assertEqual(gc.collect(), 1)
def test_dict():
def test_dict(self):
d = {}
d[1] = d
gc.collect()
del d
expect(gc.collect(), 1, "dict")
self.assertEqual(gc.collect(), 1)
def test_tuple():
def test_tuple(self):
# since tuples are immutable we close the loop with a list
l = []
t = (l,)
@ -41,40 +58,40 @@ def test_tuple():
gc.collect()
del t
del l
expect(gc.collect(), 2, "tuple")
self.assertEqual(gc.collect(), 2)
def test_class():
def test_class(self):
class A:
pass
A.a = A
gc.collect()
del A
expect_nonzero(gc.collect(), "class")
self.assertNotEqual(gc.collect(), 0)
def test_newstyleclass():
def test_newstyleclass(self):
class A(object):
pass
gc.collect()
del A
expect_nonzero(gc.collect(), "staticclass")
self.assertNotEqual(gc.collect(), 0)
def test_instance():
def test_instance(self):
class A:
pass
a = A()
a.a = a
gc.collect()
del a
expect_nonzero(gc.collect(), "instance")
self.assertNotEqual(gc.collect(), 0)
def test_newinstance():
def test_newinstance(self):
class A(object):
pass
a = A()
a.a = a
gc.collect()
del a
expect_nonzero(gc.collect(), "newinstance")
self.assertNotEqual(gc.collect(), 0)
class B(list):
pass
class C(B, A):
@ -83,15 +100,15 @@ def test_newinstance():
a.a = a
gc.collect()
del a
expect_nonzero(gc.collect(), "newinstance(2)")
self.assertNotEqual(gc.collect(), 0)
del B, C
expect_nonzero(gc.collect(), "newinstance(3)")
self.assertNotEqual(gc.collect(), 0)
A.a = A()
del A
expect_nonzero(gc.collect(), "newinstance(4)")
expect(gc.collect(), 0, "newinstance(5)")
self.assertNotEqual(gc.collect(), 0)
self.assertEqual(gc.collect(), 0)
def test_method():
def test_method(self):
# Tricky: self.__init__ is a bound method, it references the instance.
class A:
def __init__(self):
@ -99,9 +116,9 @@ def test_method():
a = A()
gc.collect()
del a
expect_nonzero(gc.collect(), "method")
self.assertNotEqual(gc.collect(), 0)
def test_finalizer():
def test_finalizer(self):
# A() is uncollectable if it is part of a cycle, make sure it shows up
# in gc.garbage.
class A:
@ -116,16 +133,16 @@ def test_finalizer():
gc.collect()
del a
del b
expect_nonzero(gc.collect(), "finalizer")
self.assertNotEqual(gc.collect(), 0)
for obj in gc.garbage:
if id(obj) == id_a:
del obj.a
break
else:
raise TestFailed, "didn't find obj in garbage (finalizer)"
self.fail("didn't find obj in garbage (finalizer)")
gc.garbage.remove(obj)
def test_finalizer_newclass():
def test_finalizer_newclass(self):
# A() is uncollectable if it is part of a cycle, make sure it shows up
# in gc.garbage.
class A(object):
@ -140,40 +157,40 @@ def test_finalizer_newclass():
gc.collect()
del a
del b
expect_nonzero(gc.collect(), "finalizer")
self.assertNotEqual(gc.collect(), 0)
for obj in gc.garbage:
if id(obj) == id_a:
del obj.a
break
else:
raise TestFailed, "didn't find obj in garbage (finalizer)"
self.fail("didn't find obj in garbage (finalizer)")
gc.garbage.remove(obj)
def test_function():
def test_function(self):
# 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
expect(gc.collect(), 2, "function")
self.assertEqual(gc.collect(), 2)
def test_frame():
def test_frame(self):
def f():
frame = sys._getframe()
gc.collect()
f()
expect(gc.collect(), 1, "frame")
self.assertEqual(gc.collect(), 1)
def test_saveall():
def test_saveall(self):
# Verify that cyclic garbage like lists show up in gc.garbage if the
# SAVEALL option is enabled.
# First make sure we don't save away other stuff that just happens to
# be waiting for collection.
gc.collect()
vereq(gc.garbage, []) # if this fails, someone else created immortal trash
# if this fails, someone else created immortal trash
self.assertEqual(gc.garbage, [])
L = []
L.append(L)
@ -185,11 +202,11 @@ def test_saveall():
gc.collect()
gc.set_debug(debug)
vereq(len(gc.garbage), 1)
self.assertEqual(len(gc.garbage), 1)
obj = gc.garbage.pop()
vereq(id(obj), id_L)
self.assertEqual(id(obj), id_L)
def test_del():
def test_del(self):
# __del__ methods can trigger collection, make this to happen
thresholds = gc.get_threshold()
gc.enable()
@ -204,7 +221,7 @@ def test_del():
gc.disable()
gc.set_threshold(*thresholds)
def test_del_newclass():
def test_del_newclass(self):
# __del__ methods can trigger collection, make this to happen
thresholds = gc.get_threshold()
gc.enable()
@ -219,22 +236,23 @@ def test_del_newclass():
gc.disable()
gc.set_threshold(*thresholds)
def test_get_count():
def test_get_count(self):
gc.collect()
expect(gc.get_count(), (0, 0, 0), "get_count()")
self.assertEqual(gc.get_count(), (0, 0, 0))
a = dict()
expect(gc.get_count(), (1, 0, 0), "get_count()")
self.assertEqual(gc.get_count(), (1, 0, 0))
def test_collect_generations():
def test_collect_generations(self):
gc.collect()
a = dict()
gc.collect(0)
expect(gc.get_count(), (0, 1, 0), "collect(0)")
self.assertEqual(gc.get_count(), (0, 1, 0))
gc.collect(1)
expect(gc.get_count(), (0, 0, 1), "collect(1)")
self.assertEqual(gc.get_count(), (0, 0, 1))
gc.collect(2)
expect(gc.get_count(), (0, 0, 0), "collect(1)")
self.assertEqual(gc.get_count(), (0, 0, 0))
def test_trashcan(self):
class Ouch:
n = 0
def __del__(self):
@ -242,7 +260,6 @@ class Ouch:
if Ouch.n % 17 == 0:
gc.collect()
def test_trashcan():
# "trashcan" is a hack to prevent stack overflow when deallocating
# very deeply nested tuples etc. It works in part by abusing the
# type pointer and refcount fields, and that can yield horrible
@ -270,12 +287,12 @@ def test_trashcan():
v = {1: v, 2: Ouch()}
gc.disable()
def test_boom(self):
class Boom:
def __getattr__(self, someattribute):
del self.attr
raise AttributeError
def test_boom():
a = Boom()
b = Boom()
a.attr = b
@ -284,16 +301,17 @@ def test_boom():
gc.collect()
garbagelen = len(gc.garbage)
del a, b
# a<->b are in a trash cycle now. Collection will invoke Boom.__getattr__
# (to see whether a and b have __del__ methods), and __getattr__ deletes
# the internal "attr" attributes as a side effect. That causes the
# trash cycle to get reclaimed via refcounts falling to 0, thus mutating
# the trash graph as a side effect of merely asking whether __del__
# exists. This used to (before 2.3b1) crash Python. Now __getattr__
# isn't called.
expect(gc.collect(), 4, "boom")
expect(len(gc.garbage), garbagelen, "boom")
# a<->b are in a trash cycle now. Collection will invoke
# Boom.__getattr__ (to see whether a and b have __del__ methods), and
# __getattr__ deletes the internal "attr" attributes as a side effect.
# That causes the trash cycle to get reclaimed via refcounts falling to
# 0, thus mutating the trash graph as a side effect of merely asking
# whether __del__ exists. This used to (before 2.3b1) crash Python.
# Now __getattr__ isn't called.
self.assertEqual(gc.collect(), 4)
self.assertEqual(len(gc.garbage), garbagelen)
def test_boom2(self):
class Boom2:
def __init__(self):
self.x = 0
@ -304,7 +322,6 @@ class Boom2:
del self.attr
raise AttributeError
def test_boom2():
a = Boom2()
b = Boom2()
a.attr = b
@ -316,11 +333,12 @@ def test_boom2():
# Much like test_boom(), except that __getattr__ doesn't break the
# cycle until the second time gc checks for __del__. As of 2.3b1,
# there isn't a second time, so this simply cleans up the trash cycle.
# We expect a, b, a.__dict__ and b.__dict__ (4 objects) to get reclaimed
# this way.
expect(gc.collect(), 4, "boom2")
expect(len(gc.garbage), garbagelen, "boom2")
# We expect a, b, a.__dict__ and b.__dict__ (4 objects) to get
# reclaimed this way.
self.assertEqual(gc.collect(), 4)
self.assertEqual(len(gc.garbage), garbagelen)
def test_boom_new(self):
# boom__new and boom2_new are exactly like boom and boom2, except use
# new-style classes.
@ -329,7 +347,6 @@ class Boom_New(object):
del self.attr
raise AttributeError
def test_boom_new():
a = Boom_New()
b = Boom_New()
a.attr = b
@ -338,9 +355,10 @@ def test_boom_new():
gc.collect()
garbagelen = len(gc.garbage)
del a, b
expect(gc.collect(), 4, "boom_new")
expect(len(gc.garbage), garbagelen, "boom_new")
self.assertEqual(gc.collect(), 4)
self.assertEqual(len(gc.garbage), garbagelen)
def test_boom2_new(self):
class Boom2_New(object):
def __init__(self):
self.x = 0
@ -351,7 +369,6 @@ class Boom2_New(object):
del self.attr
raise AttributeError
def test_boom2_new():
a = Boom2_New()
b = Boom2_New()
a.attr = b
@ -360,57 +377,33 @@ def test_boom2_new():
gc.collect()
garbagelen = len(gc.garbage)
del a, b
expect(gc.collect(), 4, "boom2_new")
expect(len(gc.garbage), garbagelen, "boom2_new")
self.assertEqual(gc.collect(), 4)
self.assertEqual(len(gc.garbage), garbagelen)
def test_get_referents():
def test_get_referents(self):
alist = [1, 3, 5]
got = gc.get_referents(alist)
got.sort()
expect(got, alist, "get_referents")
self.assertEqual(got, alist)
atuple = tuple(alist)
got = gc.get_referents(atuple)
got.sort()
expect(got, alist, "get_referents")
self.assertEqual(got, alist)
adict = {1: 3, 5: 7}
expected = [1, 3, 5, 7]
got = gc.get_referents(adict)
got.sort()
expect(got, expected, "get_referents")
self.assertEqual(got, expected)
got = gc.get_referents([1, 2], {3: 4}, (0, 0, 0))
got.sort()
expect(got, [0, 0] + range(5), "get_referents")
self.assertEqual(got, [0, 0] + range(5))
expect(gc.get_referents(1, 'a', 4j), [], "get_referents")
self.assertEqual(gc.get_referents(1, 'a', 4j), [])
# Bug 1055820 has several tests of longstanding bugs involving weakrefs and
# cyclic gc.
# An instance of C1055820 has a self-loop, so becomes cyclic trash when
# unreachable.
class C1055820(object):
def __init__(self, i):
self.i = i
self.loop = self
class GC_Detector(object):
# Create an instance I. Then gc hasn't happened again so long as
# I.gc_happened is false.
def __init__(self):
self.gc_happened = False
def it_happened(ignored):
self.gc_happened = True
# Create a piece of cyclic trash that triggers it_happened when
# gc collects it.
self.wr = weakref.ref(C1055820(666), it_happened)
def test_bug1055820b():
def test_bug1055820b(self):
# Corresponds to temp2b.py in the bug report.
ouch = []
@ -422,20 +415,28 @@ def test_bug1055820b():
c = None
gc.collect()
expect(len(ouch), 0, "bug1055820b")
self.assertEqual(len(ouch), 0)
# Make the two instances trash, and collect again. The bug was that
# the callback materialized a strong reference to an instance, but gc
# cleared the instance's dict anyway.
Cs = None
gc.collect()
expect(len(ouch), 2, "bug1055820b") # else the callbacks didn't run
self.assertEqual(len(ouch), 2) # else the callbacks didn't run
for x in ouch:
# If the callback resurrected one of these guys, the instance
# would be damaged, with an empty __dict__.
expect(x, None, "bug1055820b")
self.assertEqual(x, None)
def test_bug1055820c():
# Corresponds to temp2c.py in the bug report. This is pretty elaborate.
class GCTogglingTests(unittest.TestCase):
def setUp(self):
gc.enable()
def tearDown(self):
gc.disable()
def test_bug1055820c(self):
# Corresponds to temp2c.py in the bug report. This is pretty
# elaborate.
c0 = C1055820(0)
# Move c0 into generation 2.
@ -458,11 +459,11 @@ def test_bug1055820c():
c0 = c1 = c2 = None
# What we've set up: c0, c1, and c2 are all trash now. c0 is in
# generation 2. The only thing keeping it alive is that c1 points to it.
# c1 and c2 are in generation 0, and are in self-loops. There's a global
# weakref to c2 (c2wr), but that weakref has no callback. There's also
# a global weakref to c0 (c0wr), and that does have a callback, and that
# callback references c2 via c2wr().
# generation 2. The only thing keeping it alive is that c1 points to
# it. c1 and c2 are in generation 0, and are in self-loops. There's a
# global weakref to c2 (c2wr), but that weakref has no callback.
# There's also a global weakref to c0 (c0wr), and that does have a
# callback, and that callback references c2 via c2wr().
#
# c0 has a wr with callback, which references c2wr
# ^
@ -476,14 +477,14 @@ def test_bug1055820c():
# | | | |
# <--v <--v
#
# So this is the nightmare: when generation 0 gets collected, we see that
# c2 has a callback-free weakref, and c1 doesn't even have a weakref.
# Collecting generation 0 doesn't see c0 at all, and c0 is the only object
# that has a weakref with a callback. gc clears c1 and c2. Clearing c1
# has the side effect of dropping the refcount on c0 to 0, so c0 goes
# away (despite that it's in an older generation) and c0's wr callback
# triggers. That in turn materializes a reference to c2 via c2wr(), but
# c2 gets cleared anyway by gc.
# So this is the nightmare: when generation 0 gets collected, we see
# that c2 has a callback-free weakref, and c1 doesn't even have a
# weakref. Collecting generation 0 doesn't see c0 at all, and c0 is
# the only object that has a weakref with a callback. gc clears c1
# and c2. Clearing c1 has the side effect of dropping the refcount on
# c0 to 0, so c0 goes away (despite that it's in an older generation)
# and c0's wr callback triggers. That in turn materializes a reference
# to c2 via c2wr(), but c2 gets cleared anyway by gc.
# We want to let gc happen "naturally", to preserve the distinction
# between generations.
@ -493,17 +494,17 @@ def test_bug1055820c():
while not detector.gc_happened:
i += 1
if i > 10000:
raise TestFailed("gc didn't happen after 10000 iterations")
expect(len(ouch), 0, "bug1055820c")
self.fail("gc didn't happen after 10000 iterations")
self.assertEqual(len(ouch), 0)
junk.append([]) # this will eventually trigger gc
expect(len(ouch), 1, "bug1055820c") # else the callback wasn't invoked
self.assertEqual(len(ouch), 1) # else the callback wasn't invoked
for x in ouch:
# If the callback resurrected c2, the instance would be damaged,
# with an empty __dict__.
expect(x, None, "bug1055820c")
self.assertEqual(x, None)
def test_bug1055820d():
def test_bug1055820d(self):
# Corresponds to temp2d.py in the bug report. This is very much like
# test_bug1055820c, but uses a __del__ method instead of a weakref
# callback to sneak in a resurrection of cyclic trash.
@ -527,10 +528,10 @@ def test_bug1055820d():
d0 = c1 = c2 = None
# What we've set up: d0, c1, and c2 are all trash now. d0 is in
# generation 2. The only thing keeping it alive is that c1 points to it.
# c1 and c2 are in generation 0, and are in self-loops. There's a global
# weakref to c2 (c2wr), but that weakref has no callback. There are no
# other weakrefs.
# generation 2. The only thing keeping it alive is that c1 points to
# it. c1 and c2 are in generation 0, and are in self-loops. There's
# a global weakref to c2 (c2wr), but that weakref has no callback.
# There are no other weakrefs.
#
# d0 has a __del__ method that references c2wr
# ^
@ -544,13 +545,13 @@ def test_bug1055820d():
# | | | |
# <--v <--v
#
# So this is the nightmare: when generation 0 gets collected, we see that
# c2 has a callback-free weakref, and c1 doesn't even have a weakref.
# Collecting generation 0 doesn't see d0 at all. gc clears c1 and c2.
# Clearing c1 has the side effect of dropping the refcount on d0 to 0, so
# d0 goes away (despite that it's in an older generation) and d0's __del__
# triggers. That in turn materializes a reference to c2 via c2wr(), but
# c2 gets cleared anyway by gc.
# So this is the nightmare: when generation 0 gets collected, we see
# that c2 has a callback-free weakref, and c1 doesn't even have a
# weakref. Collecting generation 0 doesn't see d0 at all. gc clears
# c1 and c2. Clearing c1 has the side effect of dropping the refcount
# on d0 to 0, so d0 goes away (despite that it's in an older
# generation) and d0's __del__ triggers. That in turn materializes
# a reference to c2 via c2wr(), but c2 gets cleared anyway by gc.
# We want to let gc happen "naturally", to preserve the distinction
# between generations.
@ -560,67 +561,26 @@ def test_bug1055820d():
while not detector.gc_happened:
i += 1
if i > 10000:
raise TestFailed("gc didn't happen after 10000 iterations")
expect(len(ouch), 0, "bug1055820d")
self.fail("gc didn't happen after 10000 iterations")
self.assertEqual(len(ouch), 0)
junk.append([]) # this will eventually trigger gc
expect(len(ouch), 1, "bug1055820d") # else __del__ wasn't invoked
self.assertEqual(len(ouch), 1) # else __del__ wasn't invoked
for x in ouch:
# If __del__ resurrected c2, the instance would be damaged, with an
# empty __dict__.
expect(x, None, "bug1055820d")
self.assertEqual(x, None)
def test_all():
gc.collect() # Delete 2nd generation garbage
run_test("lists", test_list)
run_test("dicts", test_dict)
run_test("tuples", test_tuple)
run_test("classes", test_class)
run_test("new style classes", test_newstyleclass)
run_test("instances", test_instance)
run_test("new instances", test_newinstance)
run_test("methods", test_method)
run_test("functions", test_function)
run_test("frames", test_frame)
run_test("finalizers", test_finalizer)
run_test("finalizers (new class)", test_finalizer_newclass)
run_test("__del__", test_del)
run_test("__del__ (new class)", test_del_newclass)
run_test("get_count()", test_get_count)
run_test("collect(n)", test_collect_generations)
run_test("saveall", test_saveall)
run_test("trashcan", test_trashcan)
run_test("boom", test_boom)
run_test("boom2", test_boom2)
run_test("boom_new", test_boom_new)
run_test("boom2_new", test_boom2_new)
run_test("get_referents", test_get_referents)
run_test("bug1055820b", test_bug1055820b)
gc.enable()
try:
run_test("bug1055820c", test_bug1055820c)
finally:
gc.disable()
gc.enable()
try:
run_test("bug1055820d", test_bug1055820d)
finally:
gc.disable()
def test():
if verbose:
print "disabling automatic collection"
def test_main():
enabled = gc.isenabled()
gc.disable()
verify(not gc.isenabled())
assert not gc.isenabled()
debug = gc.get_debug()
gc.set_debug(debug & ~gc.DEBUG_LEAK) # this test is supposed to leak
try:
test_all()
gc.collect() # Delete 2nd generation garbage
run_unittest(GCTests, GCTogglingTests)
finally:
gc.set_debug(debug)
# test gc.enable() even if GC is disabled by default
@ -628,9 +588,9 @@ def test():
print "restoring automatic collection"
# make sure to always test gc.enable()
gc.enable()
verify(gc.isenabled())
assert gc.isenabled()
if not enabled:
gc.disable()
test()
if __name__ == "__main__":
test_main()