cpython/Lib/test/test_threading_local.py

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import unittest
from doctest import DocTestSuite
from test import test_support
import threading
import weakref
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import gc
class Weak(object):
pass
def target(local, weaklist):
weak = Weak()
local.weak = weak
weaklist.append(weakref.ref(weak))
class ThreadingLocalTest(unittest.TestCase):
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def test_local_refs(self):
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self._local_refs(20)
self._local_refs(50)
self._local_refs(100)
def _local_refs(self, n):
local = threading.local()
weaklist = []
for i in range(n):
t = threading.Thread(target=target, args=(local, weaklist))
t.start()
t.join()
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del t
gc.collect()
self.assertEqual(len(weaklist), n)
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# XXX threading.local keeps the local of the last stopped thread alive.
deadlist = [weak for weak in weaklist if weak() is None]
self.assertEqual(len(deadlist), n-1)
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# Assignment to the same thread local frees it sometimes (!)
local.someothervar = None
gc.collect()
deadlist = [weak for weak in weaklist if weak() is None]
self.assert_(len(deadlist) in (n-1, n), (n, len(deadlist)))
def test_derived(self):
# Issue 3088: if there is a threads switch inside the __init__
# of a threading.local derived class, the per-thread dictionary
# is created but not correctly set on the object.
# The first member set may be bogus.
import time
class Local(threading.local):
def __init__(self):
time.sleep(0.01)
local = Local()
def f(i):
local.x = i
# Simply check that the variable is correctly set
self.assertEqual(local.x, i)
threads= []
for i in range(10):
t = threading.Thread(target=f, args=(i,))
t.start()
threads.append(t)
for t in threads:
t.join()
def test_derived_cycle_dealloc(self):
# http://bugs.python.org/issue6990
class Local(threading.local):
pass
locals = None
passed = [False]
e1 = threading.Event()
e2 = threading.Event()
def f():
# 1) Involve Local in a cycle
cycle = [Local()]
cycle.append(cycle)
cycle[0].foo = 'bar'
# 2) GC the cycle (triggers threadmodule.c::local_clear
# before local_dealloc)
del cycle
gc.collect()
e1.set()
e2.wait()
# 4) New Locals should be empty
passed[0] = all(not hasattr(local, 'foo') for local in locals)
t = threading.Thread(target=f)
t.start()
e1.wait()
# 3) New Locals should recycle the original's address. Creating
# them in the thread overwrites the thread state and avoids the
# bug
locals = [Local() for i in range(10)]
e2.set()
t.join()
self.assertTrue(passed[0])
def test_main():
suite = unittest.TestSuite()
suite.addTest(DocTestSuite('_threading_local'))
suite.addTest(unittest.makeSuite(ThreadingLocalTest))
try:
from thread import _local
except ImportError:
pass
else:
import _threading_local
local_orig = _threading_local.local
def setUp(test):
_threading_local.local = _local
def tearDown(test):
_threading_local.local = local_orig
suite.addTest(DocTestSuite('_threading_local',
setUp=setUp, tearDown=tearDown)
)
test_support.run_unittest(suite)
if __name__ == '__main__':
test_main()