FCL/sf/adapt/qemu: comparison symbian-qemu-0.9.1-12/python-2.6.1/Lib/test/test

equal deleted inserted replaced

-:ffa851df0825
+:2fb8b9db1c86
+import unittest
+from test.test_support import verbose, run_unittest
+import sys
+import gc
+import weakref
+### Support code
+###############################################################################
+# 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)
+### Tests
+###############################################################################
+class GCTests(unittest.TestCase):
+def test_list(self):
+l = []
+l.append(l)
+gc.collect()
+del l
+self.assertEqual(gc.collect(), 1)
+def test_dict(self):
+d = {}
+d[1] = d
+gc.collect()
+del d
+self.assertEqual(gc.collect(), 1)
+def test_tuple(self):
+# since tuples are immutable we close the loop with a list
+l = []
+t = (l,)
+l.append(t)
+gc.collect()
+del t
+del l
+self.assertEqual(gc.collect(), 2)
+def test_class(self):
+class A:
+pass
+A.a = A
+gc.collect()
+del A
+self.assertNotEqual(gc.collect(), 0)
+def test_newstyleclass(self):
+class A(object):
+pass
+gc.collect()
+del A
+self.assertNotEqual(gc.collect(), 0)
+def test_instance(self):
+class A:
+pass
+a = A()
+a.a = a
+gc.collect()
+del a
+self.assertNotEqual(gc.collect(), 0)
+def test_newinstance(self):
+class A(object):
+pass
+a = A()
+a.a = a
+gc.collect()
+del a
+self.assertNotEqual(gc.collect(), 0)
+class B(list):
+pass
+class C(B, A):
+pass
+a = C()
+a.a = a
+gc.collect()
+del a
+self.assertNotEqual(gc.collect(), 0)
+del B, C
+self.assertNotEqual(gc.collect(), 0)
+A.a = A()
+del A
+self.assertNotEqual(gc.collect(), 0)
+self.assertEqual(gc.collect(), 0)
+def test_method(self):
+# 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
+self.assertNotEqual(gc.collect(), 0)
+def test_finalizer(self):
+# 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
+self.assertNotEqual(gc.collect(), 0)
+for obj in gc.garbage:
+if id(obj) == id_a:
+del obj.a
+break
+else:
+self.fail("didn't find obj in garbage (finalizer)")
+gc.garbage.remove(obj)
+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):
+def __del__(self): pass
+class B(object):
+pass
+a = A()
+a.a = a
+id_a = id(a)
+b = B()
+b.b = b
+gc.collect()
+del a
+del b
+self.assertNotEqual(gc.collect(), 0)
+for obj in gc.garbage:
+if id(obj) == id_a:
+del obj.a
+break
+else:
+self.fail("didn't find obj in garbage (finalizer)")
+gc.garbage.remove(obj)
+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
+self.assertEqual(gc.collect(), 2)
+def test_frame(self):
+def f():
+frame = sys._getframe()
+gc.collect()
+f()
+self.assertEqual(gc.collect(), 1)
+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()
+# if this fails, someone else created immortal trash
+self.assertEqual(gc.garbage, [])
+L = []
+L.append(L)
+id_L = id(L)
+debug = gc.get_debug()
+gc.set_debug(debug | gc.DEBUG_SAVEALL)
+del L
+gc.collect()
+gc.set_debug(debug)
+self.assertEqual(len(gc.garbage), 1)
+obj = gc.garbage.pop()
+self.assertEqual(id(obj), id_L)
+def test_del(self):
+# __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()
+gc.set_threshold(*thresholds)
+def test_del_newclass(self):
+# __del__ methods can trigger collection, make this to happen
+thresholds = gc.get_threshold()
+gc.enable()
+gc.set_threshold(1)
+class A(object):
+def __del__(self):
+dir(self)
+a = A()
+del a
+gc.disable()
+gc.set_threshold(*thresholds)
+# The following two tests are fragile:
+# They precisely count the number of allocations,
+# which is highly implementation-dependent.
+# For example:
+# - disposed tuples are not freed, but reused
+# - the call to assertEqual somehow avoids building its args tuple
+def test_get_count(self):
+# Avoid future allocation of method object
+assertEqual = self.assertEqual
+gc.collect()
+assertEqual(gc.get_count(), (0, 0, 0))
+a = dict()
+# since gc.collect(), we created two objects:
+# the dict, and the tuple returned by get_count()
+assertEqual(gc.get_count(), (2, 0, 0))
+def test_collect_generations(self):
+# Avoid future allocation of method object
+assertEqual = self.assertEqual
+gc.collect()
+a = dict()
+gc.collect(0)
+assertEqual(gc.get_count(), (0, 1, 0))
+gc.collect(1)
+assertEqual(gc.get_count(), (0, 0, 1))
+gc.collect(2)
+assertEqual(gc.get_count(), (0, 0, 0))
+def test_trashcan(self):
+class Ouch:
+n = 0
+def __del__(self):
+Ouch.n = Ouch.n + 1
+if Ouch.n % 17 == 0:
+gc.collect()
+# "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
+# problems when gc tries to traverse the structures.
+# If this test fails (as it does in 2.0, 2.1 and 2.2), it will
+# most likely die via segfault.
+# Note:  In 2.3 the possibility for compiling without cyclic gc was
+# removed, and that in turn allows the trashcan mechanism to work
+# via much simpler means (e.g., it never abuses the type pointer or
+# refcount fields anymore).  Since it's much less likely to cause a
+# problem now, the various constants in this expensive (we force a lot
+# of full collections) test are cut back from the 2.2 version.
+gc.enable()
+N = 150
+for count in range(2):
+t = []
+for i in range(N):
+t = [t, Ouch()]
+u = []
+for i in range(N):
+u = [u, Ouch()]
+v = {}
+for i in range(N):
+v = {1: v, 2: Ouch()}
+gc.disable()
+def test_boom(self):
+class Boom:
+def __getattr__(self, someattribute):
+del self.attr
+raise AttributeError
+a = Boom()
+b = Boom()
+a.attr = b
+b.attr = a
+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.
+self.assertEqual(gc.collect(), 4)
+self.assertEqual(len(gc.garbage), garbagelen)
+def test_boom2(self):
+class Boom2:
+def __init__(self):
+self.x = 0
+def __getattr__(self, someattribute):
+self.x += 1
+if self.x > 1:
+del self.attr
+raise AttributeError
+a = Boom2()
+b = Boom2()
+a.attr = b
+b.attr = a
+gc.collect()
+garbagelen = len(gc.garbage)
+del a, b
+# 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.
+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.
+class Boom_New(object):
+def __getattr__(self, someattribute):
+del self.attr
+raise AttributeError
+a = Boom_New()
+b = Boom_New()
+a.attr = b
+b.attr = a
+gc.collect()
+garbagelen = len(gc.garbage)
+del a, b
+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
+def __getattr__(self, someattribute):
+self.x += 1
+if self.x > 1:
+del self.attr
+raise AttributeError
+a = Boom2_New()
+b = Boom2_New()
+a.attr = b
+b.attr = a
+gc.collect()
+garbagelen = len(gc.garbage)
+del a, b
+self.assertEqual(gc.collect(), 4)
+self.assertEqual(len(gc.garbage), garbagelen)
+def test_get_referents(self):
+alist = [1, 3, 5]
+got = gc.get_referents(alist)
+got.sort()
+self.assertEqual(got, alist)
+atuple = tuple(alist)
+got = gc.get_referents(atuple)
+got.sort()
+self.assertEqual(got, alist)
+adict = {1: 3, 5: 7}
+expected = [1, 3, 5, 7]
+got = gc.get_referents(adict)
+got.sort()
+self.assertEqual(got, expected)
+got = gc.get_referents([1, 2], {3: 4}, (0, 0, 0))
+got.sort()
+self.assertEqual(got, [0, 0] + range(5))
+self.assertEqual(gc.get_referents(1, 'a', 4j), [])
+def test_bug1055820b(self):
+# Corresponds to temp2b.py in the bug report.
+ouch = []
+def callback(ignored):
+ouch[:] = [wr() for wr in WRs]
+Cs = [C1055820(i) for i in range(2)]
+WRs = [weakref.ref(c, callback) for c in Cs]
+c = None
+gc.collect()
+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()
+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__.
+self.assertEqual(x, None)
+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.
+gc.collect()
+c1 = C1055820(1)
+c1.keep_c0_alive = c0
+del c0.loop # now only c1 keeps c0 alive
+c2 = C1055820(2)
+c2wr = weakref.ref(c2) # no callback!
+ouch = []
+def callback(ignored):
+ouch[:] = [c2wr()]
+# The callback gets associated with a wr on an object in generation 2.
+c0wr = weakref.ref(c0, callback)
+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().
+#
+#               c0 has a wr with callback, which references c2wr
+#               ^
+#               |
+#               |     Generation 2 above dots
+#. . . . . . . .|. . . . . . . . . . . . . . . . . . . . . . . .
+#               |     Generation 0 below dots
+#               |
+#               |
+#            ^->c1   ^->c2 has a wr but no callback
+#            |  |    |  |
+#            <--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.
+# We want to let gc happen "naturally", to preserve the distinction
+# between generations.
+junk = []
+i = 0
+detector = GC_Detector()
+while not detector.gc_happened:
+i += 1
+if i > 10000:
+self.fail("gc didn't happen after 10000 iterations")
+self.assertEqual(len(ouch), 0)
+junk.append([])  # this will eventually trigger gc
+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__.
+self.assertEqual(x, None)
+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.
+ouch = []
+class D(C1055820):
+def __del__(self):
+ouch[:] = [c2wr()]
+d0 = D(0)
+# Move all the above into generation 2.
+gc.collect()
+c1 = C1055820(1)
+c1.keep_d0_alive = d0
+del d0.loop # now only c1 keeps d0 alive
+c2 = C1055820(2)
+c2wr = weakref.ref(c2) # no callback!
+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.
+#
+#               d0 has a __del__ method that references c2wr
+#               ^
+#               |
+#               |     Generation 2 above dots
+#. . . . . . . .|. . . . . . . . . . . . . . . . . . . . . . . .
+#               |     Generation 0 below dots
+#               |
+#               |
+#            ^->c1   ^->c2 has a wr but no callback
+#            |  |    |  |
+#            <--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.
+# We want to let gc happen "naturally", to preserve the distinction
+# between generations.
+detector = GC_Detector()
+junk = []
+i = 0
+while not detector.gc_happened:
+i += 1
+if i > 10000:
+self.fail("gc didn't happen after 10000 iterations")
+self.assertEqual(len(ouch), 0)
+junk.append([])  # this will eventually trigger gc
+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__.
+self.assertEqual(x, None)
+def test_main():
+enabled = gc.isenabled()
+gc.disable()
+assert not gc.isenabled()
+debug = gc.get_debug()
+gc.set_debug(debug & ~gc.DEBUG_LEAK) # this test is supposed to leak
+try:
+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
+if verbose:
+print "restoring automatic collection"
+# make sure to always test gc.enable()
+gc.enable()
+assert gc.isenabled()
+if not enabled:
+gc.disable()
+if __name__ == "__main__":
+test_main()