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12385a5f86
Attempting to add() and remove() an object related by a 'through' model now raises more descriptive AttributeErrors, in line with set and create().
385 lines
14 KiB
Python
385 lines
14 KiB
Python
from __future__ import unicode_literals
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from datetime import datetime
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from operator import attrgetter
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from django.test import TestCase
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from .models import (Person, Group, Membership, CustomMembership,
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PersonSelfRefM2M, Friendship)
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class M2mThroughTests(TestCase):
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def setUp(self):
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self.bob = Person.objects.create(name='Bob')
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self.jim = Person.objects.create(name='Jim')
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self.jane = Person.objects.create(name='Jane')
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self.rock = Group.objects.create(name='Rock')
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self.roll = Group.objects.create(name='Roll')
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def test_m2m_through(self):
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# We start out by making sure that the Group 'rock' has no members.
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self.assertQuerysetEqual(
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self.rock.members.all(),
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[]
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)
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# To make Jim a member of Group Rock, simply create a Membership object.
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Membership.objects.create(person=self.jim, group=self.rock)
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# We can do the same for Jane and Rock.
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Membership.objects.create(person=self.jane, group=self.rock)
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# Let's check to make sure that it worked. Jane and Jim should be members of Rock.
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self.assertQuerysetEqual(
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self.rock.members.all(), [
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'Jane',
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'Jim'
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],
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attrgetter("name")
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)
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# Now we can add a bunch more Membership objects to test with.
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Membership.objects.create(person=self.bob, group=self.roll)
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Membership.objects.create(person=self.jim, group=self.roll)
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Membership.objects.create(person=self.jane, group=self.roll)
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# We can get Jim's Group membership as with any ForeignKey.
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self.assertQuerysetEqual(
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self.jim.group_set.all(), [
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'Rock',
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'Roll'
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],
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attrgetter("name")
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)
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# Querying the intermediary model works like normal.
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self.assertEqual(
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repr(Membership.objects.get(person=self.jane, group=self.rock)),
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'<Membership: Jane is a member of Rock>'
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)
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# It's not only get that works. Filter works like normal as well.
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self.assertQuerysetEqual(
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Membership.objects.filter(person=self.jim), [
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'<Membership: Jim is a member of Rock>',
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'<Membership: Jim is a member of Roll>'
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]
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)
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self.rock.members.clear()
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# Now there will be no members of Rock.
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self.assertQuerysetEqual(
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self.rock.members.all(),
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[]
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)
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def test_forward_descriptors(self):
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# Due to complications with adding via an intermediary model,
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# the add method raises an error.
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self.assertRaisesMessage(
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AttributeError,
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'Cannot use add() on a ManyToManyField which specifies an intermediary model',
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lambda: self.rock.members.add(self.bob)
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)
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# Create is also disabled as it suffers from the same problems as add.
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self.assertRaisesMessage(
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AttributeError,
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'Cannot use create() on a ManyToManyField which specifies an intermediary model',
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lambda: self.rock.members.create(name='Anne')
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)
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# Remove has similar complications, and it also raises an error.
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self.assertRaisesMessage(
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AttributeError,
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'Cannot use remove() on a ManyToManyField which specifies an intermediary model',
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lambda: self.rock.members.remove(self.jim)
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)
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m1 = Membership.objects.create(person=self.jim, group=self.rock)
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m2 = Membership.objects.create(person=self.jane, group=self.rock)
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# Here we back up the list of all members of Rock.
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backup = list(self.rock.members.all())
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# ...and we verify that it has worked.
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self.assertEqual(
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[p.name for p in backup],
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['Jane', 'Jim']
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)
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# The clear function should still work.
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self.rock.members.clear()
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# Now there will be no members of Rock.
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self.assertQuerysetEqual(
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self.rock.members.all(),
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[]
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)
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# Assignment should not work with models specifying a through model for
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# many of the same reasons as adding.
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self.assertRaisesMessage(
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AttributeError,
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'Cannot set values on a ManyToManyField which specifies an intermediary model',
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setattr,
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self.rock,
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"members",
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backup
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)
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# Let's re-save those instances that we've cleared.
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m1.save()
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m2.save()
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# Verifying that those instances were re-saved successfully.
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self.assertQuerysetEqual(
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self.rock.members.all(), [
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'Jane',
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'Jim'
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],
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attrgetter("name")
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)
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def test_reverse_descriptors(self):
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# Due to complications with adding via an intermediary model,
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# the add method is not provided.
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self.assertRaisesMessage(
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AttributeError,
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'Cannot use add() on a ManyToManyField which specifies an intermediary model',
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lambda: self.bob.group_set.add(self.rock)
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)
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# Create is also disabled as it suffers from the same problems as add.
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self.assertRaisesMessage(
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AttributeError,
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'Cannot use create() on a ManyToManyField which specifies an intermediary model',
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lambda: self.bob.group_set.create(name="funk")
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)
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# Remove has similar complications, and is not provided either.
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self.assertRaisesMessage(
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AttributeError,
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'Cannot use remove() on a ManyToManyField which specifies an intermediary model',
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lambda: self.jim.group_set.remove(self.rock)
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)
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m1 = Membership.objects.create(person=self.jim, group=self.rock)
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m2 = Membership.objects.create(person=self.jim, group=self.roll)
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# Here we back up the list of all of Jim's groups.
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backup = list(self.jim.group_set.all())
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self.assertEqual(
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[g.name for g in backup],
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['Rock', 'Roll']
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)
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# The clear function should still work.
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self.jim.group_set.clear()
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# Now Jim will be in no groups.
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self.assertQuerysetEqual(
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self.jim.group_set.all(),
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[]
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)
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# Assignment should not work with models specifying a through model for
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# many of the same reasons as adding.
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self.assertRaisesMessage(
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AttributeError,
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'Cannot set values on a ManyToManyField which specifies an intermediary model',
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setattr,
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self.jim,
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"group_set",
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backup
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)
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# Let's re-save those instances that we've cleared.
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m1.save()
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m2.save()
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# Verifying that those instances were re-saved successfully.
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self.assertQuerysetEqual(
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self.jim.group_set.all(), [
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'Rock',
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'Roll'
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],
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attrgetter("name")
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)
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def test_custom_tests(self):
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# Let's see if we can query through our second relationship.
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self.assertQuerysetEqual(
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self.rock.custom_members.all(),
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[]
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)
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# We can query in the opposite direction as well.
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self.assertQuerysetEqual(
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self.bob.custom.all(),
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[]
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)
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CustomMembership.objects.create(person=self.bob, group=self.rock)
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CustomMembership.objects.create(person=self.jim, group=self.rock)
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# If we get the number of people in Rock, it should be both Bob and Jim.
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self.assertQuerysetEqual(
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self.rock.custom_members.all(), [
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'Bob',
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'Jim'
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],
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attrgetter("name")
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)
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# Bob should only be in one custom group.
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self.assertQuerysetEqual(
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self.bob.custom.all(), [
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'Rock'
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],
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attrgetter("name")
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)
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# Let's make sure our new descriptors don't conflict with the FK related_name.
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self.assertQuerysetEqual(
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self.bob.custom_person_related_name.all(), [
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'<CustomMembership: Bob is a member of Rock>'
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]
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)
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def test_self_referential_tests(self):
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# Let's first create a person who has no friends.
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tony = PersonSelfRefM2M.objects.create(name="Tony")
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self.assertQuerysetEqual(
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tony.friends.all(),
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[]
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)
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chris = PersonSelfRefM2M.objects.create(name="Chris")
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Friendship.objects.create(first=tony, second=chris, date_friended=datetime.now())
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# Tony should now show that Chris is his friend.
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self.assertQuerysetEqual(
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tony.friends.all(), [
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'Chris'
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],
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attrgetter("name")
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)
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# But we haven't established that Chris is Tony's Friend.
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self.assertQuerysetEqual(
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chris.friends.all(),
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[]
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)
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Friendship.objects.create(first=chris, second=tony, date_friended=datetime.now())
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# Having added Chris as a friend, let's make sure that his friend set reflects
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# that addition.
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self.assertQuerysetEqual(
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chris.friends.all(), [
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'Tony'
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],
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attrgetter("name")
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)
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# Chris gets mad and wants to get rid of all of his friends.
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chris.friends.clear()
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# Now he should not have any more friends.
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self.assertQuerysetEqual(
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chris.friends.all(),
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[]
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)
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# Since this isn't a symmetrical relation, Tony's friend link still exists.
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self.assertQuerysetEqual(
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tony.friends.all(), [
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'Chris'
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],
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attrgetter("name")
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)
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def test_query_tests(self):
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Membership.objects.create(person=self.jim, group=self.rock)
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m2 = Membership.objects.create(person=self.jane, group=self.rock)
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m3 = Membership.objects.create(person=self.bob, group=self.roll)
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Membership.objects.create(person=self.jim, group=self.roll)
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m5 = Membership.objects.create(person=self.jane, group=self.roll)
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m2.invite_reason = "She was just awesome."
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m2.date_joined = datetime(2006, 1, 1)
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m2.save()
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m3.date_joined = datetime(2004, 1, 1)
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m3.save()
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m5.date_joined = datetime(2004, 1, 1)
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m5.save()
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# We can query for the related model by using its attribute name (members, in
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# this case).
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self.assertQuerysetEqual(
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Group.objects.filter(members__name='Bob'), [
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'Roll'
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],
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attrgetter("name")
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)
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# To query through the intermediary model, we specify its model name.
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# In this case, membership.
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self.assertQuerysetEqual(
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Group.objects.filter(membership__invite_reason="She was just awesome."), [
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'Rock'
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],
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attrgetter("name")
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)
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# If we want to query in the reverse direction by the related model, use its
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# model name (group, in this case).
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self.assertQuerysetEqual(
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Person.objects.filter(group__name="Rock"), [
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'Jane',
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'Jim'
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],
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attrgetter("name")
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)
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CustomMembership.objects.create(person=self.bob, group=self.rock)
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CustomMembership.objects.create(person=self.jim, group=self.rock)
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# If the m2m field has specified a related_name, using that will work.
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self.assertQuerysetEqual(
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Person.objects.filter(custom__name="Rock"), [
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'Bob',
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'Jim'
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],
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attrgetter("name")
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)
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# To query through the intermediary model in the reverse direction, we again
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# specify its model name (membership, in this case).
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self.assertQuerysetEqual(
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Person.objects.filter(membership__invite_reason="She was just awesome."), [
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'Jane'
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],
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attrgetter("name")
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)
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# Let's see all of the groups that Jane joined after 1 Jan 2005:
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self.assertQuerysetEqual(
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Group.objects.filter(membership__date_joined__gt=datetime(2005, 1, 1), membership__person=self.jane), [
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'Rock'
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],
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attrgetter("name")
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)
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# Queries also work in the reverse direction: Now let's see all of the people
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# that have joined Rock since 1 Jan 2005:
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self.assertQuerysetEqual(
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Person.objects.filter(membership__date_joined__gt=datetime(2005, 1, 1), membership__group=self.rock), [
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'Jane',
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'Jim'
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],
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attrgetter("name")
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)
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# Conceivably, queries through membership could return correct, but non-unique
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# querysets. To demonstrate this, we query for all people who have joined a
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# group after 2004:
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self.assertQuerysetEqual(
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Person.objects.filter(membership__date_joined__gt=datetime(2004, 1, 1)), [
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'Jane',
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'Jim',
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'Jim'
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],
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attrgetter("name")
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)
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# Jim showed up twice, because he joined two groups ('Rock', and 'Roll'):
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self.assertEqual(
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[(m.person.name, m.group.name) for m in Membership.objects.filter(date_joined__gt=datetime(2004, 1, 1))],
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[('Jane', 'Rock'), ('Jim', 'Rock'), ('Jim', 'Roll')]
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)
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# QuerySet's distinct() method can correct this problem.
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self.assertQuerysetEqual(
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Person.objects.filter(membership__date_joined__gt=datetime(2004, 1, 1)).distinct(), [
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'Jane',
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'Jim'
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],
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attrgetter("name")
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)
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