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django/tests/m2m_signals/tests.py
2022-02-07 20:37:05 +01:00

579 lines
19 KiB
Python

"""
Testing signals emitted on changing m2m relations.
"""
from django.db import models
from django.test import TestCase
from .models import Car, Part, Person, SportsCar
class ManyToManySignalsTest(TestCase):
@classmethod
def setUpTestData(cls):
cls.vw = Car.objects.create(name="VW")
cls.bmw = Car.objects.create(name="BMW")
cls.toyota = Car.objects.create(name="Toyota")
cls.wheelset = Part.objects.create(name="Wheelset")
cls.doors = Part.objects.create(name="Doors")
cls.engine = Part.objects.create(name="Engine")
cls.airbag = Part.objects.create(name="Airbag")
cls.sunroof = Part.objects.create(name="Sunroof")
cls.alice = Person.objects.create(name="Alice")
cls.bob = Person.objects.create(name="Bob")
cls.chuck = Person.objects.create(name="Chuck")
cls.daisy = Person.objects.create(name="Daisy")
def setUp(self):
self.m2m_changed_messages = []
def m2m_changed_signal_receiver(self, signal, sender, **kwargs):
message = {
"instance": kwargs["instance"],
"action": kwargs["action"],
"reverse": kwargs["reverse"],
"model": kwargs["model"],
}
if kwargs["pk_set"]:
message["objects"] = list(
kwargs["model"].objects.filter(pk__in=kwargs["pk_set"])
)
self.m2m_changed_messages.append(message)
def tearDown(self):
# disconnect all signal handlers
models.signals.m2m_changed.disconnect(
self.m2m_changed_signal_receiver, Car.default_parts.through
)
models.signals.m2m_changed.disconnect(
self.m2m_changed_signal_receiver, Car.optional_parts.through
)
models.signals.m2m_changed.disconnect(
self.m2m_changed_signal_receiver, Person.fans.through
)
models.signals.m2m_changed.disconnect(
self.m2m_changed_signal_receiver, Person.friends.through
)
def _initialize_signal_car(self, add_default_parts_before_set_signal=False):
"""Install a listener on the two m2m relations."""
models.signals.m2m_changed.connect(
self.m2m_changed_signal_receiver, Car.optional_parts.through
)
if add_default_parts_before_set_signal:
# adding a default part to our car - no signal listener installed
self.vw.default_parts.add(self.sunroof)
models.signals.m2m_changed.connect(
self.m2m_changed_signal_receiver, Car.default_parts.through
)
def test_pk_set_on_repeated_add_remove(self):
"""
m2m_changed is always fired, even for repeated calls to the same
method, but the behavior of pk_sets differs by action.
- For signals related to `add()`, only PKs that will actually be
inserted are sent.
- For `remove()` all PKs are sent, even if they will not affect the DB.
"""
pk_sets_sent = []
def handler(signal, sender, **kwargs):
if kwargs["action"] in ["pre_add", "pre_remove"]:
pk_sets_sent.append(kwargs["pk_set"])
models.signals.m2m_changed.connect(handler, Car.default_parts.through)
self.vw.default_parts.add(self.wheelset)
self.vw.default_parts.add(self.wheelset)
self.vw.default_parts.remove(self.wheelset)
self.vw.default_parts.remove(self.wheelset)
expected_pk_sets = [
{self.wheelset.pk},
set(),
{self.wheelset.pk},
{self.wheelset.pk},
]
self.assertEqual(pk_sets_sent, expected_pk_sets)
models.signals.m2m_changed.disconnect(handler, Car.default_parts.through)
def test_m2m_relations_add_remove_clear(self):
expected_messages = []
self._initialize_signal_car(add_default_parts_before_set_signal=True)
self.vw.default_parts.add(self.wheelset, self.doors, self.engine)
expected_messages.append(
{
"instance": self.vw,
"action": "pre_add",
"reverse": False,
"model": Part,
"objects": [self.doors, self.engine, self.wheelset],
}
)
expected_messages.append(
{
"instance": self.vw,
"action": "post_add",
"reverse": False,
"model": Part,
"objects": [self.doors, self.engine, self.wheelset],
}
)
self.assertEqual(self.m2m_changed_messages, expected_messages)
# give the BMW and Toyota some doors as well
self.doors.car_set.add(self.bmw, self.toyota)
expected_messages.append(
{
"instance": self.doors,
"action": "pre_add",
"reverse": True,
"model": Car,
"objects": [self.bmw, self.toyota],
}
)
expected_messages.append(
{
"instance": self.doors,
"action": "post_add",
"reverse": True,
"model": Car,
"objects": [self.bmw, self.toyota],
}
)
self.assertEqual(self.m2m_changed_messages, expected_messages)
def test_m2m_relations_signals_remove_relation(self):
self._initialize_signal_car()
# remove the engine from the self.vw and the airbag (which is not set
# but is returned)
self.vw.default_parts.remove(self.engine, self.airbag)
self.assertEqual(
self.m2m_changed_messages,
[
{
"instance": self.vw,
"action": "pre_remove",
"reverse": False,
"model": Part,
"objects": [self.airbag, self.engine],
},
{
"instance": self.vw,
"action": "post_remove",
"reverse": False,
"model": Part,
"objects": [self.airbag, self.engine],
},
],
)
def test_m2m_relations_signals_give_the_self_vw_some_optional_parts(self):
expected_messages = []
self._initialize_signal_car()
# give the self.vw some optional parts (second relation to same model)
self.vw.optional_parts.add(self.airbag, self.sunroof)
expected_messages.append(
{
"instance": self.vw,
"action": "pre_add",
"reverse": False,
"model": Part,
"objects": [self.airbag, self.sunroof],
}
)
expected_messages.append(
{
"instance": self.vw,
"action": "post_add",
"reverse": False,
"model": Part,
"objects": [self.airbag, self.sunroof],
}
)
self.assertEqual(self.m2m_changed_messages, expected_messages)
# add airbag to all the cars (even though the self.vw already has one)
self.airbag.cars_optional.add(self.vw, self.bmw, self.toyota)
expected_messages.append(
{
"instance": self.airbag,
"action": "pre_add",
"reverse": True,
"model": Car,
"objects": [self.bmw, self.toyota],
}
)
expected_messages.append(
{
"instance": self.airbag,
"action": "post_add",
"reverse": True,
"model": Car,
"objects": [self.bmw, self.toyota],
}
)
self.assertEqual(self.m2m_changed_messages, expected_messages)
def test_m2m_relations_signals_reverse_relation_with_custom_related_name(self):
self._initialize_signal_car()
# remove airbag from the self.vw (reverse relation with custom
# related_name)
self.airbag.cars_optional.remove(self.vw)
self.assertEqual(
self.m2m_changed_messages,
[
{
"instance": self.airbag,
"action": "pre_remove",
"reverse": True,
"model": Car,
"objects": [self.vw],
},
{
"instance": self.airbag,
"action": "post_remove",
"reverse": True,
"model": Car,
"objects": [self.vw],
},
],
)
def test_m2m_relations_signals_clear_all_parts_of_the_self_vw(self):
self._initialize_signal_car()
# clear all parts of the self.vw
self.vw.default_parts.clear()
self.assertEqual(
self.m2m_changed_messages,
[
{
"instance": self.vw,
"action": "pre_clear",
"reverse": False,
"model": Part,
},
{
"instance": self.vw,
"action": "post_clear",
"reverse": False,
"model": Part,
},
],
)
def test_m2m_relations_signals_all_the_doors_off_of_cars(self):
self._initialize_signal_car()
# take all the doors off of cars
self.doors.car_set.clear()
self.assertEqual(
self.m2m_changed_messages,
[
{
"instance": self.doors,
"action": "pre_clear",
"reverse": True,
"model": Car,
},
{
"instance": self.doors,
"action": "post_clear",
"reverse": True,
"model": Car,
},
],
)
def test_m2m_relations_signals_reverse_relation(self):
self._initialize_signal_car()
# take all the airbags off of cars (clear reverse relation with custom
# related_name)
self.airbag.cars_optional.clear()
self.assertEqual(
self.m2m_changed_messages,
[
{
"instance": self.airbag,
"action": "pre_clear",
"reverse": True,
"model": Car,
},
{
"instance": self.airbag,
"action": "post_clear",
"reverse": True,
"model": Car,
},
],
)
def test_m2m_relations_signals_alternative_ways(self):
expected_messages = []
self._initialize_signal_car()
# alternative ways of setting relation:
self.vw.default_parts.create(name="Windows")
p6 = Part.objects.get(name="Windows")
expected_messages.append(
{
"instance": self.vw,
"action": "pre_add",
"reverse": False,
"model": Part,
"objects": [p6],
}
)
expected_messages.append(
{
"instance": self.vw,
"action": "post_add",
"reverse": False,
"model": Part,
"objects": [p6],
}
)
self.assertEqual(self.m2m_changed_messages, expected_messages)
# direct assignment clears the set first, then adds
self.vw.default_parts.set([self.wheelset, self.doors, self.engine])
expected_messages.append(
{
"instance": self.vw,
"action": "pre_remove",
"reverse": False,
"model": Part,
"objects": [p6],
}
)
expected_messages.append(
{
"instance": self.vw,
"action": "post_remove",
"reverse": False,
"model": Part,
"objects": [p6],
}
)
expected_messages.append(
{
"instance": self.vw,
"action": "pre_add",
"reverse": False,
"model": Part,
"objects": [self.doors, self.engine, self.wheelset],
}
)
expected_messages.append(
{
"instance": self.vw,
"action": "post_add",
"reverse": False,
"model": Part,
"objects": [self.doors, self.engine, self.wheelset],
}
)
self.assertEqual(self.m2m_changed_messages, expected_messages)
def test_m2m_relations_signals_clearing_removing(self):
expected_messages = []
self._initialize_signal_car(add_default_parts_before_set_signal=True)
# set by clearing.
self.vw.default_parts.set([self.wheelset, self.doors, self.engine], clear=True)
expected_messages.append(
{
"instance": self.vw,
"action": "pre_clear",
"reverse": False,
"model": Part,
}
)
expected_messages.append(
{
"instance": self.vw,
"action": "post_clear",
"reverse": False,
"model": Part,
}
)
expected_messages.append(
{
"instance": self.vw,
"action": "pre_add",
"reverse": False,
"model": Part,
"objects": [self.doors, self.engine, self.wheelset],
}
)
expected_messages.append(
{
"instance": self.vw,
"action": "post_add",
"reverse": False,
"model": Part,
"objects": [self.doors, self.engine, self.wheelset],
}
)
self.assertEqual(self.m2m_changed_messages, expected_messages)
# set by only removing what's necessary.
self.vw.default_parts.set([self.wheelset, self.doors], clear=False)
expected_messages.append(
{
"instance": self.vw,
"action": "pre_remove",
"reverse": False,
"model": Part,
"objects": [self.engine],
}
)
expected_messages.append(
{
"instance": self.vw,
"action": "post_remove",
"reverse": False,
"model": Part,
"objects": [self.engine],
}
)
self.assertEqual(self.m2m_changed_messages, expected_messages)
def test_m2m_relations_signals_when_inheritance(self):
expected_messages = []
self._initialize_signal_car(add_default_parts_before_set_signal=True)
# Signals still work when model inheritance is involved
c4 = SportsCar.objects.create(name="Bugatti", price="1000000")
c4b = Car.objects.get(name="Bugatti")
c4.default_parts.set([self.doors])
expected_messages.append(
{
"instance": c4,
"action": "pre_add",
"reverse": False,
"model": Part,
"objects": [self.doors],
}
)
expected_messages.append(
{
"instance": c4,
"action": "post_add",
"reverse": False,
"model": Part,
"objects": [self.doors],
}
)
self.assertEqual(self.m2m_changed_messages, expected_messages)
self.engine.car_set.add(c4)
expected_messages.append(
{
"instance": self.engine,
"action": "pre_add",
"reverse": True,
"model": Car,
"objects": [c4b],
}
)
expected_messages.append(
{
"instance": self.engine,
"action": "post_add",
"reverse": True,
"model": Car,
"objects": [c4b],
}
)
self.assertEqual(self.m2m_changed_messages, expected_messages)
def _initialize_signal_person(self):
# Install a listener on the two m2m relations.
models.signals.m2m_changed.connect(
self.m2m_changed_signal_receiver, Person.fans.through
)
models.signals.m2m_changed.connect(
self.m2m_changed_signal_receiver, Person.friends.through
)
def test_m2m_relations_with_self_add_friends(self):
self._initialize_signal_person()
self.alice.friends.set([self.bob, self.chuck])
self.assertEqual(
self.m2m_changed_messages,
[
{
"instance": self.alice,
"action": "pre_add",
"reverse": False,
"model": Person,
"objects": [self.bob, self.chuck],
},
{
"instance": self.alice,
"action": "post_add",
"reverse": False,
"model": Person,
"objects": [self.bob, self.chuck],
},
],
)
def test_m2m_relations_with_self_add_fan(self):
self._initialize_signal_person()
self.alice.fans.set([self.daisy])
self.assertEqual(
self.m2m_changed_messages,
[
{
"instance": self.alice,
"action": "pre_add",
"reverse": False,
"model": Person,
"objects": [self.daisy],
},
{
"instance": self.alice,
"action": "post_add",
"reverse": False,
"model": Person,
"objects": [self.daisy],
},
],
)
def test_m2m_relations_with_self_add_idols(self):
self._initialize_signal_person()
self.chuck.idols.set([self.alice, self.bob])
self.assertEqual(
self.m2m_changed_messages,
[
{
"instance": self.chuck,
"action": "pre_add",
"reverse": True,
"model": Person,
"objects": [self.alice, self.bob],
},
{
"instance": self.chuck,
"action": "post_add",
"reverse": True,
"model": Person,
"objects": [self.alice, self.bob],
},
],
)