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from unittest import mock
from django.apps.registry import Apps
from django.db import models
from django.db.models import signals
from django.dispatch import receiver
from django.test import SimpleTestCase, TestCase
from django.test.utils import isolate_apps
from .models import Author, Book, Car, Person
class BaseSignalSetup:
def setUp(self):
# Save up the number of connected signals so that we can check at the
# end that all the signals we register get properly unregistered (#9989)
self.pre_signals = (
len(signals.pre_save.receivers),
len(signals.post_save.receivers),
len(signals.pre_delete.receivers),
len(signals.post_delete.receivers),
)
def tearDown(self):
# All our signals got disconnected properly.
post_signals = (
len(signals.pre_save.receivers),
len(signals.post_save.receivers),
len(signals.pre_delete.receivers),
len(signals.post_delete.receivers),
)
self.assertEqual(self.pre_signals, post_signals)
class SignalTests(BaseSignalSetup, TestCase):
def test_model_pre_init_and_post_init(self):
data = []
def pre_init_callback(sender, args, **kwargs):
data.append(kwargs['kwargs'])
signals.pre_init.connect(pre_init_callback)
def post_init_callback(sender, instance, **kwargs):
data.append(instance)
signals.post_init.connect(post_init_callback)
p1 = Person(first_name="John", last_name="Doe")
self.assertEqual(data, [{}, p1])
def test_save_signals(self):
data = []
def pre_save_handler(signal, sender, instance, **kwargs):
data.append(
(instance, sender, kwargs.get("raw", False))
)
def post_save_handler(signal, sender, instance, **kwargs):
data.append(
(instance, sender, kwargs.get("created"), kwargs.get("raw", False))
)
signals.pre_save.connect(pre_save_handler, weak=False)
signals.post_save.connect(post_save_handler, weak=False)
try:
p1 = Person.objects.create(first_name="John", last_name="Smith")
self.assertEqual(data, [
(p1, Person, False),
(p1, Person, True, False),
])
data[:] = []
p1.first_name = "Tom"
p1.save()
self.assertEqual(data, [
(p1, Person, False),
(p1, Person, False, False),
])
data[:] = []
# Calling an internal method purely so that we can trigger a "raw" save.
p1.save_base(raw=True)
self.assertEqual(data, [
(p1, Person, True),
(p1, Person, False, True),
])
data[:] = []
p2 = Person(first_name="James", last_name="Jones")
p2.id = 99999
p2.save()
self.assertEqual(data, [
(p2, Person, False),
(p2, Person, True, False),
])
data[:] = []
p2.id = 99998
p2.save()
self.assertEqual(data, [
(p2, Person, False),
(p2, Person, True, False),
])
# The sender should stay the same when using defer().
data[:] = []
p3 = Person.objects.defer('first_name').get(pk=p1.pk)
p3.last_name = 'Reese'
p3.save()
self.assertEqual(data, [
(p3, Person, False),
(p3, Person, False, False),
])
finally:
signals.pre_save.disconnect(pre_save_handler)
signals.post_save.disconnect(post_save_handler)
def test_delete_signals(self):
data = []
def pre_delete_handler(signal, sender, instance, **kwargs):
data.append(
(instance, sender, instance.id is None)
)
# #8285: signals can be any callable
class PostDeleteHandler:
def __init__(self, data):
self.data = data
def __call__(self, signal, sender, instance, **kwargs):
self.data.append(
(instance, sender, instance.id is None)
)
post_delete_handler = PostDeleteHandler(data)
signals.pre_delete.connect(pre_delete_handler, weak=False)
signals.post_delete.connect(post_delete_handler, weak=False)
try:
p1 = Person.objects.create(first_name="John", last_name="Smith")
p1.delete()
self.assertEqual(data, [
(p1, Person, False),
(p1, Person, False),
])
data[:] = []
p2 = Person(first_name="James", last_name="Jones")
p2.id = 99999
p2.save()
p2.id = 99998
p2.save()
p2.delete()
self.assertEqual(data, [
(p2, Person, False),
(p2, Person, False),
])
data[:] = []
self.assertQuerysetEqual(
Person.objects.all(), [
"James Jones",
],
str
)
finally:
signals.pre_delete.disconnect(pre_delete_handler)
signals.post_delete.disconnect(post_delete_handler)
def test_decorators(self):
data = []
@receiver(signals.pre_save, weak=False)
def decorated_handler(signal, sender, instance, **kwargs):
data.append(instance)
@receiver(signals.pre_save, sender=Car, weak=False)
def decorated_handler_with_sender_arg(signal, sender, instance, **kwargs):
data.append(instance)
try:
c1 = Car.objects.create(make="Volkswagen", model="Passat")
self.assertEqual(data, [c1, c1])
finally:
signals.pre_save.disconnect(decorated_handler)
signals.pre_save.disconnect(decorated_handler_with_sender_arg, sender=Car)
def test_save_and_delete_signals_with_m2m(self):
data = []
def pre_save_handler(signal, sender, instance, **kwargs):
data.append('pre_save signal, %s' % instance)
if kwargs.get('raw'):
data.append('Is raw')
def post_save_handler(signal, sender, instance, **kwargs):
data.append('post_save signal, %s' % instance)
if 'created' in kwargs:
if kwargs['created']:
data.append('Is created')
else:
data.append('Is updated')
if kwargs.get('raw'):
data.append('Is raw')
def pre_delete_handler(signal, sender, instance, **kwargs):
data.append('pre_delete signal, %s' % instance)
data.append('instance.id is not None: %s' % (instance.id is not None))
def post_delete_handler(signal, sender, instance, **kwargs):
data.append('post_delete signal, %s' % instance)
data.append('instance.id is not None: %s' % (instance.id is not None))
signals.pre_save.connect(pre_save_handler, weak=False)
signals.post_save.connect(post_save_handler, weak=False)
signals.pre_delete.connect(pre_delete_handler, weak=False)
signals.post_delete.connect(post_delete_handler, weak=False)
try:
a1 = Author.objects.create(name='Neal Stephenson')
self.assertEqual(data, [
"pre_save signal, Neal Stephenson",
"post_save signal, Neal Stephenson",
"Is created"
])
data[:] = []
b1 = Book.objects.create(name='Snow Crash')
self.assertEqual(data, [
"pre_save signal, Snow Crash",
"post_save signal, Snow Crash",
"Is created"
])
data[:] = []
# Assigning and removing to/from m2m shouldn't generate an m2m signal.
b1.authors.set([a1])
self.assertEqual(data, [])
b1.authors.set([])
self.assertEqual(data, [])
finally:
signals.pre_save.disconnect(pre_save_handler)
signals.post_save.disconnect(post_save_handler)
signals.pre_delete.disconnect(pre_delete_handler)
signals.post_delete.disconnect(post_delete_handler)
def test_disconnect_in_dispatch(self):
"""
Signals that disconnect when being called don't mess future
dispatching.
"""
class Handler:
def __init__(self, param):
self.param = param
self._run = False
def __call__(self, signal, sender, **kwargs):
self._run = True
signal.disconnect(receiver=self, sender=sender)
a, b = Handler(1), Handler(2)
signals.post_save.connect(a, sender=Person, weak=False)
signals.post_save.connect(b, sender=Person, weak=False)
Person.objects.create(first_name='John', last_name='Smith')
self.assertTrue(a._run)
self.assertTrue(b._run)
self.assertEqual(signals.post_save.receivers, [])
@mock.patch('weakref.ref')
def test_lazy_model_signal(self, ref):
def callback(sender, args, **kwargs):
pass
signals.pre_init.connect(callback)
signals.pre_init.disconnect(callback)
self.assertTrue(ref.called)
ref.reset_mock()
signals.pre_init.connect(callback, weak=False)
signals.pre_init.disconnect(callback)
ref.assert_not_called()
class LazyModelRefTests(BaseSignalSetup, SimpleTestCase):
def setUp(self):
super().setUp()
self.received = []
def receiver(self, **kwargs):
self.received.append(kwargs)
def test_invalid_sender_model_name(self):
msg = "Invalid model reference 'invalid'. String model references must be of the form 'app_label.ModelName'."
with self.assertRaisesMessage(ValueError, msg):
signals.post_init.connect(self.receiver, sender='invalid')
def test_already_loaded_model(self):
signals.post_init.connect(
self.receiver, sender='signals.Book', weak=False
)
try:
instance = Book()
self.assertEqual(self.received, [{
'signal': signals.post_init,
'sender': Book,
'instance': instance
}])
finally:
signals.post_init.disconnect(self.receiver, sender=Book)
@isolate_apps('signals', kwarg_name='apps')
def test_not_loaded_model(self, apps):
signals.post_init.connect(
self.receiver, sender='signals.Created', weak=False, apps=apps
)
try:
class Created(models.Model):
pass
instance = Created()
self.assertEqual(self.received, [{
'signal': signals.post_init, 'sender': Created, 'instance': instance
}])
finally:
signals.post_init.disconnect(self.receiver, sender=Created)
@isolate_apps('signals', kwarg_name='apps')
def test_disconnect(self, apps):
received = []
def receiver(**kwargs):
received.append(kwargs)
signals.post_init.connect(receiver, sender='signals.Created', apps=apps)
signals.post_init.disconnect(receiver, sender='signals.Created', apps=apps)
class Created(models.Model):
pass
Created()
self.assertEqual(received, [])
def test_register_model_class_senders_immediately(self):
"""
Model signals registered with model classes as senders don't use the
Apps.lazy_model_operation() mechanism.
"""
# Book isn't registered with apps2, so it will linger in
# apps2._pending_operations if ModelSignal does the wrong thing.
apps2 = Apps()
signals.post_init.connect(self.receiver, sender=Book, apps=apps2)
self.assertEqual(list(apps2._pending_operations), [])
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