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import gc
import sys
import weakref
from types import TracebackType
from django.dispatch import Signal, receiver
from django.test import SimpleTestCase
from django.test.utils import override_settings
if hasattr(sys, "pypy_version_info"):
def garbage_collect():
# Collecting weakreferences can take two collections on PyPy.
gc.collect()
gc.collect()
else:
def garbage_collect():
gc.collect()
def receiver_1_arg(val, **kwargs):
return val
class Callable:
def __call__(self, val, **kwargs):
return val
def a(self, val, **kwargs):
return val
a_signal = Signal()
b_signal = Signal()
c_signal = Signal()
d_signal = Signal(use_caching=True)
class DispatcherTests(SimpleTestCase):
def assertTestIsClean(self, signal):
"""Assert that everything has been cleaned up automatically"""
# Note that dead weakref cleanup happens as side effect of using
# the signal's receivers through the signals API. So, first do a
# call to an API method to force cleanup.
self.assertFalse(signal.has_listeners())
self.assertEqual(signal.receivers, [])
@override_settings(DEBUG=True)
def test_cannot_connect_no_kwargs(self):
def receiver_no_kwargs(sender):
pass
msg = "Signal receivers must accept keyword arguments (**kwargs)."
with self.assertRaisesMessage(ValueError, msg):
a_signal.connect(receiver_no_kwargs)
self.assertTestIsClean(a_signal)
@override_settings(DEBUG=True)
def test_cannot_connect_non_callable(self):
msg = "Signal receivers must be callable."
with self.assertRaisesMessage(TypeError, msg):
a_signal.connect(object())
self.assertTestIsClean(a_signal)
def test_send(self):
a_signal.connect(receiver_1_arg, sender=self)
result = a_signal.send(sender=self, val="test")
self.assertEqual(result, [(receiver_1_arg, "test")])
a_signal.disconnect(receiver_1_arg, sender=self)
self.assertTestIsClean(a_signal)
def test_send_no_receivers(self):
result = a_signal.send(sender=self, val="test")
self.assertEqual(result, [])
def test_send_connected_no_sender(self):
a_signal.connect(receiver_1_arg)
result = a_signal.send(sender=self, val="test")
self.assertEqual(result, [(receiver_1_arg, "test")])
a_signal.disconnect(receiver_1_arg)
self.assertTestIsClean(a_signal)
def test_send_different_no_sender(self):
a_signal.connect(receiver_1_arg, sender=object)
result = a_signal.send(sender=self, val="test")
self.assertEqual(result, [])
a_signal.disconnect(receiver_1_arg, sender=object)
self.assertTestIsClean(a_signal)
def test_garbage_collected(self):
a = Callable()
a_signal.connect(a.a, sender=self)
del a
garbage_collect()
result = a_signal.send(sender=self, val="test")
self.assertEqual(result, [])
self.assertTestIsClean(a_signal)
def test_cached_garbaged_collected(self):
"""
Make sure signal caching sender receivers don't prevent garbage
collection of senders.
"""
class sender:
pass
wref = weakref.ref(sender)
d_signal.connect(receiver_1_arg)
d_signal.send(sender, val="garbage")
del sender
garbage_collect()
try:
self.assertIsNone(wref())
finally:
# Disconnect after reference check since it flushes the tested cache.
d_signal.disconnect(receiver_1_arg)
def test_multiple_registration(self):
a = Callable()
a_signal.connect(a)
a_signal.connect(a)
a_signal.connect(a)
a_signal.connect(a)
a_signal.connect(a)
a_signal.connect(a)
result = a_signal.send(sender=self, val="test")
self.assertEqual(len(result), 1)
self.assertEqual(len(a_signal.receivers), 1)
del a
del result
garbage_collect()
self.assertTestIsClean(a_signal)
def test_uid_registration(self):
def uid_based_receiver_1(**kwargs):
pass
def uid_based_receiver_2(**kwargs):
pass
a_signal.connect(uid_based_receiver_1, dispatch_uid="uid")
a_signal.connect(uid_based_receiver_2, dispatch_uid="uid")
self.assertEqual(len(a_signal.receivers), 1)
a_signal.disconnect(dispatch_uid="uid")
self.assertTestIsClean(a_signal)
def test_send_robust_success(self):
a_signal.connect(receiver_1_arg)
result = a_signal.send_robust(sender=self, val="test")
self.assertEqual(result, [(receiver_1_arg, "test")])
a_signal.disconnect(receiver_1_arg)
self.assertTestIsClean(a_signal)
def test_send_robust_no_receivers(self):
result = a_signal.send_robust(sender=self, val="test")
self.assertEqual(result, [])
def test_send_robust_ignored_sender(self):
a_signal.connect(receiver_1_arg)
result = a_signal.send_robust(sender=self, val="test")
self.assertEqual(result, [(receiver_1_arg, "test")])
a_signal.disconnect(receiver_1_arg)
self.assertTestIsClean(a_signal)
def test_send_robust_fail(self):
def fails(val, **kwargs):
raise ValueError("this")
a_signal.connect(fails)
try:
with self.assertLogs("django.dispatch", "ERROR") as cm:
result = a_signal.send_robust(sender=self, val="test")
err = result[0][1]
self.assertIsInstance(err, ValueError)
self.assertEqual(err.args, ("this",))
self.assertIs(hasattr(err, "__traceback__"), True)
self.assertIsInstance(err.__traceback__, TracebackType)
log_record = cm.records[0]
self.assertEqual(
log_record.getMessage(),
"Error calling "
"DispatcherTests.test_send_robust_fail.<locals>.fails in "
"Signal.send_robust() (this)",
)
self.assertIsNotNone(log_record.exc_info)
_, exc_value, _ = log_record.exc_info
self.assertIsInstance(exc_value, ValueError)
self.assertEqual(str(exc_value), "this")
finally:
a_signal.disconnect(fails)
self.assertTestIsClean(a_signal)
def test_disconnection(self):
receiver_1 = Callable()
receiver_2 = Callable()
receiver_3 = Callable()
a_signal.connect(receiver_1)
a_signal.connect(receiver_2)
a_signal.connect(receiver_3)
a_signal.disconnect(receiver_1)
del receiver_2
garbage_collect()
a_signal.disconnect(receiver_3)
self.assertTestIsClean(a_signal)
def test_values_returned_by_disconnection(self):
receiver_1 = Callable()
receiver_2 = Callable()
a_signal.connect(receiver_1)
receiver_1_disconnected = a_signal.disconnect(receiver_1)
receiver_2_disconnected = a_signal.disconnect(receiver_2)
self.assertTrue(receiver_1_disconnected)
self.assertFalse(receiver_2_disconnected)
self.assertTestIsClean(a_signal)
def test_has_listeners(self):
self.assertFalse(a_signal.has_listeners())
self.assertFalse(a_signal.has_listeners(sender=object()))
receiver_1 = Callable()
a_signal.connect(receiver_1)
self.assertTrue(a_signal.has_listeners())
self.assertTrue(a_signal.has_listeners(sender=object()))
a_signal.disconnect(receiver_1)
self.assertFalse(a_signal.has_listeners())
self.assertFalse(a_signal.has_listeners(sender=object()))
class ReceiverTestCase(SimpleTestCase):
def test_receiver_single_signal(self):
@receiver(a_signal)
def f(val, **kwargs):
self.state = val
self.state = False
a_signal.send(sender=self, val=True)
self.assertTrue(self.state)
def test_receiver_signal_list(self):
@receiver([a_signal, b_signal, c_signal])
def f(val, **kwargs):
self.state.append(val)
self.state = []
a_signal.send(sender=self, val="a")
c_signal.send(sender=self, val="c")
b_signal.send(sender=self, val="b")
self.assertIn("a", self.state)
self.assertIn("b", self.state)
self.assertIn("c", self.state)
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