Python test.support.start_threads() Examples

def test_pendingcalls_threaded(self):

        #do every callback on a separate thread
        n = 32 #total callbacks
        threads = []
        class foo(object):pass
        context = foo()
        context.l = []
        context.n = 2 #submits per thread
        context.nThreads = n // context.n
        context.nFinished = 0
        context.lock = threading.Lock()
        context.event = threading.Event()

        threads = [threading.Thread(target=self.pendingcalls_thread,
                                    args=(context,))
                   for i in range(context.nThreads)]
        with support.start_threads(threads):
            self.pendingcalls_wait(context.l, n, context) 

def test_threads_write(self):
        # Issue6750: concurrent writes could duplicate data
        event = threading.Event()
        with self.open(support.TESTFN, "w", buffering=1) as f:
            def run(n):
                text = "Thread%03d\n" % n
                event.wait()
                f.write(text)
            threads = [threading.Thread(target=run, args=(x,))
                       for x in range(20)]
            with support.start_threads(threads, event.set):
                time.sleep(0.02)
        with self.open(support.TESTFN) as f:
            content = f.read()
            for n in range(20):
                self.assertEqual(content.count("Thread%03d\n" % n), 1) 

def test_pendingcalls_threaded(self):

        #do every callback on a separate thread
        n = 32 #total callbacks
        threads = []
        class foo(object):pass
        context = foo()
        context.l = []
        context.n = 2 #submits per thread
        context.nThreads = n // context.n
        context.nFinished = 0
        context.lock = threading.Lock()
        context.event = threading.Event()

        threads = [threading.Thread(target=self.pendingcalls_thread,
                                    args=(context,))
                   for i in range(context.nThreads)]
        with support.start_threads(threads):
            self.pendingcalls_wait(context.l, n, context) 

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(self._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)

        with support.start_threads(threading.Thread(target=f, args=(i,))
                                   for i in range(10)):
            pass 

def test_threads_write(self):
        # Issue6750: concurrent writes could duplicate data
        event = threading.Event()
        with self.open(support.TESTFN, "w", buffering=1) as f:
            def run(n):
                text = "Thread%03d\n" % n
                event.wait()
                f.write(text)
            threads = [threading.Thread(target=run, args=(x,))
                       for x in range(20)]
            with support.start_threads(threads, event.set):
                time.sleep(0.02)
        with self.open(support.TESTFN) as f:
            content = f.read()
            for n in range(20):
                self.assertEqual(content.count("Thread%03d\n" % n), 1) 

def test_make_msgid_collisions(self):
        # Test make_msgid uniqueness, even with multiple threads
        class MsgidsThread(Thread):
            def run(self):
                # generate msgids for 3 seconds
                self.msgids = []
                append = self.msgids.append
                make_msgid = utils.make_msgid
                try:
                    clock = time.monotonic
                except AttributeError:
                    clock = time.time
                tfin = clock() + 3.0
                while clock() < tfin:
                    append(make_msgid(domain='testdomain-string'))

        threads = [MsgidsThread() for i in range(5)]
        with start_threads(threads):
            pass
        all_ids = sum([t.msgids for t in threads], [])
        self.assertEqual(len(set(all_ids)), len(all_ids)) 

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(self._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)

        with support.start_threads(threading.Thread(target=f, args=(i,))
                                   for i in range(10)):
            pass 

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(self._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)

        with support.start_threads(threading.Thread(target=f, args=(i,))
                                   for i in range(10)):
            pass 

def test_pendingcalls_threaded(self):

        #do every callback on a separate thread
        n = 32 #total callbacks
        threads = []
        class foo(object):pass
        context = foo()
        context.l = []
        context.n = 2 #submits per thread
        context.nThreads = n // context.n
        context.nFinished = 0
        context.lock = threading.Lock()
        context.event = threading.Event()

        threads = [threading.Thread(target=self.pendingcalls_thread,
                                    args=(context,))
                   for i in range(context.nThreads)]
        with support.start_threads(threads):
            self.pendingcalls_wait(context.l, n, context) 

def test_threads_write(self):
        # Issue6750: concurrent writes could duplicate data
        event = threading.Event()
        with self.open(support.TESTFN, "w", buffering=1) as f:
            def run(n):
                text = "Thread%03d\n" % n
                event.wait()
                f.write(text)
            threads = [threading.Thread(target=run, args=(x,))
                       for x in range(20)]
            with support.start_threads(threads, event.set):
                time.sleep(0.02)
        with self.open(support.TESTFN) as f:
            content = f.read()
            for n in range(20):
                self.assertEqual(content.count("Thread%03d\n" % n), 1) 

def test_threads_write(self):
        # Issue6750: concurrent writes could duplicate data
        event = threading.Event()
        with self.open(support.TESTFN, "w", buffering=1) as f:
            def run(n):
                text = "Thread%03d\n" % n
                event.wait()
                f.write(text)
            threads = [threading.Thread(target=run, args=(x,))
                       for x in range(20)]
            with support.start_threads(threads, event.set):
                time.sleep(0.02)
        with self.open(support.TESTFN) as f:
            content = f.read()
            for n in range(20):
                self.assertEqual(content.count("Thread%03d\n" % n), 1) 

def test_main(self):
        threads = [TempFileGreedy() for i in range(NUM_THREADS)]
        with start_threads(threads, startEvent.set):
            pass
        ok = sum(t.ok_count for t in threads)
        errors = [str(t.name) + str(t.errors.getvalue())
                  for t in threads if t.error_count]

        msg = "Errors: errors %d ok %d\n%s" % (len(errors), ok,
            '\n'.join(errors))
        self.assertEqual(errors, [], msg)
        self.assertEqual(ok, NUM_THREADS * FILES_PER_THREAD) 

def testThreading(self):
        # Issue #7205: Using a BZ2File from several threads shouldn't deadlock.
        data = b"1" * 2**20
        nthreads = 10
        with BZ2File(self.filename, 'wb') as f:
            def comp():
                for i in range(5):
                    f.write(data)
            threads = [threading.Thread(target=comp) for i in range(nthreads)]
            with support.start_threads(threads):
                pass 

def test_main(self):
        threads = [TempFileGreedy() for i in range(NUM_THREADS)]
        with start_threads(threads, startEvent.set):
            pass
        ok = sum(t.ok_count for t in threads)
        errors = [str(t.name) + str(t.errors.getvalue())
                  for t in threads if t.error_count]

        msg = "Errors: errors %d ok %d\n%s" % (len(errors), ok,
            '\n'.join(errors))
        self.assertEqual(errors, [], msg)
        self.assertEqual(ok, NUM_THREADS * FILES_PER_THREAD) 

def test_threads(self):
        try:
            # Write out many bytes with exactly the same number of 0's,
            # 1's... 255's. This will help us check that concurrent reading
            # doesn't duplicate or forget contents.
            N = 1000
            l = list(range(256)) * N
            random.shuffle(l)
            s = bytes(bytearray(l))
            with self.open(support.TESTFN, "wb") as f:
                f.write(s)
            with self.open(support.TESTFN, self.read_mode, buffering=0) as raw:
                bufio = self.tp(raw, 8)
                errors = []
                results = []
                def f():
                    try:
                        # Intra-buffer read then buffer-flushing read
                        for n in cycle([1, 19]):
                            s = bufio.read(n)
                            if not s:
                                break
                            # list.append() is atomic
                            results.append(s)
                    except Exception as e:
                        errors.append(e)
                        raise
                threads = [threading.Thread(target=f) for x in range(20)]
                with support.start_threads(threads):
                    time.sleep(0.02) # yield
                self.assertFalse(errors,
                    "the following exceptions were caught: %r" % errors)
                s = b''.join(results)
                for i in range(256):
                    c = bytes(bytearray([i]))
                    self.assertEqual(s.count(c), N)
        finally:
            support.unlink(support.TESTFN) 

def test_lru_cache_threaded2(self):
        # Simultaneous call with the same arguments
        n, m = 5, 7
        start = threading.Barrier(n+1)
        pause = threading.Barrier(n+1)
        stop = threading.Barrier(n+1)
        @self.module.lru_cache(maxsize=m*n)
        def f(x):
            pause.wait(10)
            return 3 * x
        self.assertEqual(f.cache_info(), (0, 0, m*n, 0))
        def test():
            for i in range(m):
                start.wait(10)
                self.assertEqual(f(i), 3 * i)
                stop.wait(10)
        threads = [threading.Thread(target=test) for k in range(n)]
        with support.start_threads(threads):
            for i in range(m):
                start.wait(10)
                stop.reset()
                pause.wait(10)
                start.reset()
                stop.wait(10)
                pause.reset()
                self.assertEqual(f.cache_info(), (0, (i+1)*n, m*n, i+1)) 

def test_lru_cache_threaded2(self):
        # Simultaneous call with the same arguments
        n, m = 5, 7
        start = threading.Barrier(n+1)
        pause = threading.Barrier(n+1)
        stop = threading.Barrier(n+1)
        @self.module.lru_cache(maxsize=m*n)
        def f(x):
            pause.wait(10)
            return 3 * x
        self.assertEqual(f.cache_info(), (0, 0, m*n, 0))
        def test():
            for i in range(m):
                start.wait(10)
                self.assertEqual(f(i), 3 * i)
                stop.wait(10)
        threads = [threading.Thread(target=test) for k in range(n)]
        with support.start_threads(threads):
            for i in range(m):
                start.wait(10)
                stop.reset()
                pause.wait(10)
                start.reset()
                stop.wait(10)
                pause.reset()
                self.assertEqual(f.cache_info(), (0, (i+1)*n, m*n, i+1)) 

def test_threads(self):
        try:
            # Write out many bytes with exactly the same number of 0's,
            # 1's... 255's. This will help us check that concurrent reading
            # doesn't duplicate or forget contents.
            N = 1000
            l = list(range(256)) * N
            random.shuffle(l)
            s = bytes(bytearray(l))
            with self.open(support.TESTFN, "wb") as f:
                f.write(s)
            with self.open(support.TESTFN, self.read_mode, buffering=0) as raw:
                bufio = self.tp(raw, 8)
                errors = []
                results = []
                def f():
                    try:
                        # Intra-buffer read then buffer-flushing read
                        for n in cycle([1, 19]):
                            s = bufio.read(n)
                            if not s:
                                break
                            # list.append() is atomic
                            results.append(s)
                    except Exception as e:
                        errors.append(e)
                        raise
                threads = [threading.Thread(target=f) for x in range(20)]
                with support.start_threads(threads):
                    time.sleep(0.02) # yield
                self.assertFalse(errors,
                    "the following exceptions were caught: %r" % errors)
                s = b''.join(results)
                for i in range(256):
                    c = bytes(bytearray([i]))
                    self.assertEqual(s.count(c), N)
        finally:
            support.unlink(support.TESTFN) 

def test_main(self):
        threads = [TempFileGreedy() for i in range(NUM_THREADS)]
        with start_threads(threads, startEvent.set):
            pass
        ok = sum(t.ok_count for t in threads)
        errors = [str(t.name) + str(t.errors.getvalue())
                  for t in threads if t.error_count]

        msg = "Errors: errors %d ok %d\n%s" % (len(errors), ok,
            '\n'.join(errors))
        self.assertEqual(errors, [], msg)
        self.assertEqual(ok, NUM_THREADS * FILES_PER_THREAD) 

def test_threads(self):
        try:
            # Write out many bytes with exactly the same number of 0's,
            # 1's... 255's. This will help us check that concurrent reading
            # doesn't duplicate or forget contents.
            N = 1000
            l = list(range(256)) * N
            random.shuffle(l)
            s = bytes(bytearray(l))
            with self.open(support.TESTFN, "wb") as f:
                f.write(s)
            with self.open(support.TESTFN, self.read_mode, buffering=0) as raw:
                bufio = self.tp(raw, 8)
                errors = []
                results = []
                def f():
                    try:
                        # Intra-buffer read then buffer-flushing read
                        for n in cycle([1, 19]):
                            s = bufio.read(n)
                            if not s:
                                break
                            # list.append() is atomic
                            results.append(s)
                    except Exception as e:
                        errors.append(e)
                        raise
                threads = [threading.Thread(target=f) for x in range(20)]
                with support.start_threads(threads):
                    time.sleep(0.02) # yield
                self.assertFalse(errors,
                    "the following exceptions were caught: %r" % errors)
                s = b''.join(results)
                for i in range(256):
                    c = bytes(bytearray([i]))
                    self.assertEqual(s.count(c), N)
        finally:
            support.unlink(support.TESTFN) 

def testThreading(self):
        # Issue #7205: Using a BZ2File from several threads shouldn't deadlock.
        data = b"1" * 2**20
        nthreads = 10
        with BZ2File(self.filename, 'wb') as f:
            def comp():
                for i in range(5):
                    f.write(data)
            threads = [threading.Thread(target=comp) for i in range(nthreads)]
            with support.start_threads(threads):
                pass 

def test_lru_cache_threaded2(self):
        # Simultaneous call with the same arguments
        n, m = 5, 7
        start = threading.Barrier(n+1)
        pause = threading.Barrier(n+1)
        stop = threading.Barrier(n+1)
        @self.module.lru_cache(maxsize=m*n)
        def f(x):
            pause.wait(10)
            return 3 * x
        self.assertEqual(f.cache_info(), (0, 0, m*n, 0))
        def test():
            for i in range(m):
                start.wait(10)
                self.assertEqual(f(i), 3 * i)
                stop.wait(10)
        threads = [threading.Thread(target=test) for k in range(n)]
        with support.start_threads(threads):
            for i in range(m):
                start.wait(10)
                stop.reset()
                pause.wait(10)
                start.reset()
                stop.wait(10)
                pause.reset()
                self.assertEqual(f.cache_info(), (0, (i+1)*n, m*n, i+1)) 

def test_threads(self):
        try:
            # Write out many bytes with exactly the same number of 0's,
            # 1's... 255's. This will help us check that concurrent reading
            # doesn't duplicate or forget contents.
            N = 1000
            l = list(range(256)) * N
            random.shuffle(l)
            s = bytes(bytearray(l))
            with self.open(support.TESTFN, "wb") as f:
                f.write(s)
            with self.open(support.TESTFN, self.read_mode, buffering=0) as raw:
                bufio = self.tp(raw, 8)
                errors = []
                results = []
                def f():
                    try:
                        # Intra-buffer read then buffer-flushing read
                        for n in cycle([1, 19]):
                            s = bufio.read(n)
                            if not s:
                                break
                            # list.append() is atomic
                            results.append(s)
                    except Exception as e:
                        errors.append(e)
                        raise
                threads = [threading.Thread(target=f) for x in range(20)]
                with support.start_threads(threads):
                    time.sleep(0.02) # yield
                self.assertFalse(errors,
                    "the following exceptions were caught: %r" % errors)
                s = b''.join(results)
                for i in range(256):
                    c = bytes(bytearray([i]))
                    self.assertEqual(s.count(c), N)
        finally:
            support.unlink(support.TESTFN) 

def test_threads(self):
        try:
            # Write out many bytes from many threads and test they were
            # all flushed.
            N = 1000
            contents = bytes(range(256)) * N
            sizes = cycle([1, 19])
            n = 0
            queue = deque()
            while n < len(contents):
                size = next(sizes)
                queue.append(contents[n:n+size])
                n += size
            del contents
            # We use a real file object because it allows us to
            # exercise situations where the GIL is released before
            # writing the buffer to the raw streams. This is in addition
            # to concurrency issues due to switching threads in the middle
            # of Python code.
            with self.open(support.TESTFN, self.write_mode, buffering=0) as raw:
                bufio = self.tp(raw, 8)
                errors = []
                def f():
                    try:
                        while True:
                            try:
                                s = queue.popleft()
                            except IndexError:
                                return
                            bufio.write(s)
                    except Exception as e:
                        errors.append(e)
                        raise
                threads = [threading.Thread(target=f) for x in range(20)]
                with support.start_threads(threads):
                    time.sleep(0.02) # yield
                self.assertFalse(errors,
                    "the following exceptions were caught: %r" % errors)
                bufio.close()
            with self.open(support.TESTFN, "rb") as f:
                s = f.read()
            for i in range(256):
                self.assertEqual(s.count(bytes([i])), N)
        finally:
            support.unlink(support.TESTFN) 

def test_lru_cache_threaded(self):
        n, m = 5, 11
        def orig(x, y):
            return 3 * x + y
        f = self.module.lru_cache(maxsize=n*m)(orig)
        hits, misses, maxsize, currsize = f.cache_info()
        self.assertEqual(currsize, 0)

        start = threading.Event()
        def full(k):
            start.wait(10)
            for _ in range(m):
                self.assertEqual(f(k, 0), orig(k, 0))

        def clear():
            start.wait(10)
            for _ in range(2*m):
                f.cache_clear()

        orig_si = sys.getswitchinterval()
        sys.setswitchinterval(1e-6)
        try:
            # create n threads in order to fill cache
            threads = [threading.Thread(target=full, args=[k])
                       for k in range(n)]
            with support.start_threads(threads):
                start.set()

            hits, misses, maxsize, currsize = f.cache_info()
            if self.module is py_functools:
                # XXX: Why can be not equal?
                self.assertLessEqual(misses, n)
                self.assertLessEqual(hits, m*n - misses)
            else:
                self.assertEqual(misses, n)
                self.assertEqual(hits, m*n - misses)
            self.assertEqual(currsize, n)

            # create n threads in order to fill cache and 1 to clear it
            threads = [threading.Thread(target=clear)]
            threads += [threading.Thread(target=full, args=[k])
                        for k in range(n)]
            start.clear()
            with support.start_threads(threads):
                start.set()
        finally:
            sys.setswitchinterval(orig_si) 

def test_threads(self):
        try:
            # Write out many bytes from many threads and test they were
            # all flushed.
            N = 1000
            contents = bytes(range(256)) * N
            sizes = cycle([1, 19])
            n = 0
            queue = deque()
            while n < len(contents):
                size = next(sizes)
                queue.append(contents[n:n+size])
                n += size
            del contents
            # We use a real file object because it allows us to
            # exercise situations where the GIL is released before
            # writing the buffer to the raw streams. This is in addition
            # to concurrency issues due to switching threads in the middle
            # of Python code.
            with self.open(support.TESTFN, self.write_mode, buffering=0) as raw:
                bufio = self.tp(raw, 8)
                errors = []
                def f():
                    try:
                        while True:
                            try:
                                s = queue.popleft()
                            except IndexError:
                                return
                            bufio.write(s)
                    except Exception as e:
                        errors.append(e)
                        raise
                threads = [threading.Thread(target=f) for x in range(20)]
                with support.start_threads(threads):
                    time.sleep(0.02) # yield
                self.assertFalse(errors,
                    "the following exceptions were caught: %r" % errors)
                bufio.close()
            with self.open(support.TESTFN, "rb") as f:
                s = f.read()
            for i in range(256):
                self.assertEqual(s.count(bytes([i])), N)
        finally:
            support.unlink(support.TESTFN) 

def test_lru_cache_threaded(self):
        n, m = 5, 11
        def orig(x, y):
            return 3 * x + y
        f = self.module.lru_cache(maxsize=n*m)(orig)
        hits, misses, maxsize, currsize = f.cache_info()
        self.assertEqual(currsize, 0)

        start = threading.Event()
        def full(k):
            start.wait(10)
            for _ in range(m):
                self.assertEqual(f(k, 0), orig(k, 0))

        def clear():
            start.wait(10)
            for _ in range(2*m):
                f.cache_clear()

        orig_si = sys.getswitchinterval()
        sys.setswitchinterval(1e-6)
        try:
            # create n threads in order to fill cache
            threads = [threading.Thread(target=full, args=[k])
                       for k in range(n)]
            with support.start_threads(threads):
                start.set()

            hits, misses, maxsize, currsize = f.cache_info()
            if self.module is py_functools:
                # XXX: Why can be not equal?
                self.assertLessEqual(misses, n)
                self.assertLessEqual(hits, m*n - misses)
            else:
                self.assertEqual(misses, n)
                self.assertEqual(hits, m*n - misses)
            self.assertEqual(currsize, n)

            # create n threads in order to fill cache and 1 to clear it
            threads = [threading.Thread(target=clear)]
            threads += [threading.Thread(target=full, args=[k])
                        for k in range(n)]
            start.clear()
            with support.start_threads(threads):
                start.set()
        finally:
            sys.setswitchinterval(orig_si) 

def test_threads(self):
        try:
            # Write out many bytes from many threads and test they were
            # all flushed.
            N = 1000
            contents = bytes(range(256)) * N
            sizes = cycle([1, 19])
            n = 0
            queue = deque()
            while n < len(contents):
                size = next(sizes)
                queue.append(contents[n:n+size])
                n += size
            del contents
            # We use a real file object because it allows us to
            # exercise situations where the GIL is released before
            # writing the buffer to the raw streams. This is in addition
            # to concurrency issues due to switching threads in the middle
            # of Python code.
            with self.open(support.TESTFN, self.write_mode, buffering=0) as raw:
                bufio = self.tp(raw, 8)
                errors = []
                def f():
                    try:
                        while True:
                            try:
                                s = queue.popleft()
                            except IndexError:
                                return
                            bufio.write(s)
                    except Exception as e:
                        errors.append(e)
                        raise
                threads = [threading.Thread(target=f) for x in range(20)]
                with support.start_threads(threads):
                    time.sleep(0.02) # yield
                self.assertFalse(errors,
                    "the following exceptions were caught: %r" % errors)
                bufio.close()
            with self.open(support.TESTFN, "rb") as f:
                s = f.read()
            for i in range(256):
                self.assertEqual(s.count(bytes([i])), N)
        finally:
            support.unlink(support.TESTFN) 

def test_threads(self):
        try:
            # Write out many bytes from many threads and test they were
            # all flushed.
            N = 1000
            contents = bytes(range(256)) * N
            sizes = cycle([1, 19])
            n = 0
            queue = deque()
            while n < len(contents):
                size = next(sizes)
                queue.append(contents[n:n+size])
                n += size
            del contents
            # We use a real file object because it allows us to
            # exercise situations where the GIL is released before
            # writing the buffer to the raw streams. This is in addition
            # to concurrency issues due to switching threads in the middle
            # of Python code.
            with self.open(support.TESTFN, self.write_mode, buffering=0) as raw:
                bufio = self.tp(raw, 8)
                errors = []
                def f():
                    try:
                        while True:
                            try:
                                s = queue.popleft()
                            except IndexError:
                                return
                            bufio.write(s)
                    except Exception as e:
                        errors.append(e)
                        raise
                threads = [threading.Thread(target=f) for x in range(20)]
                with support.start_threads(threads):
                    time.sleep(0.02) # yield
                self.assertFalse(errors,
                    "the following exceptions were caught: %r" % errors)
                bufio.close()
            with self.open(support.TESTFN, "rb") as f:
                s = f.read()
            for i in range(256):
                self.assertEqual(s.count(bytes([i])), N)
        finally:
            support.unlink(support.TESTFN) 

def test_lru_cache_threaded(self):
        n, m = 5, 11
        def orig(x, y):
            return 3 * x + y
        f = self.module.lru_cache(maxsize=n*m)(orig)
        hits, misses, maxsize, currsize = f.cache_info()
        self.assertEqual(currsize, 0)

        start = threading.Event()
        def full(k):
            start.wait(10)
            for _ in range(m):
                self.assertEqual(f(k, 0), orig(k, 0))

        def clear():
            start.wait(10)
            for _ in range(2*m):
                f.cache_clear()

        orig_si = sys.getswitchinterval()
        support.setswitchinterval(1e-6)
        try:
            # create n threads in order to fill cache
            threads = [threading.Thread(target=full, args=[k])
                       for k in range(n)]
            with support.start_threads(threads):
                start.set()

            hits, misses, maxsize, currsize = f.cache_info()
            if self.module is py_functools:
                # XXX: Why can be not equal?
                self.assertLessEqual(misses, n)
                self.assertLessEqual(hits, m*n - misses)
            else:
                self.assertEqual(misses, n)
                self.assertEqual(hits, m*n - misses)
            self.assertEqual(currsize, n)

            # create n threads in order to fill cache and 1 to clear it
            threads = [threading.Thread(target=clear)]
            threads += [threading.Thread(target=full, args=[k])
                        for k in range(n)]
            start.clear()
            with support.start_threads(threads):
                start.set()
        finally:
            sys.setswitchinterval(orig_si)