def test_multiple_gfk(self):
# Simple tests for multiple GenericForeignKeys
# only uses one model, since the above tests should be sufficient.
tiger = Animal.objects.create(common_name="tiger", latin_name='')
cheetah = Animal.objects.create(common_name="cheetah", latin_name='')
bear = Animal.objects.create(common_name="bear", latin_name="bear")
# Create directly
Comparison.objects.create(
first_obj=cheetah, other_obj=tiger, comparative="faster"
)
Comparison.objects.create(
first_obj=tiger, other_obj=cheetah, comparative="cooler"
)
# Create using GenericRelation
tiger.comparisons.create(other_obj=bear, comparative="cooler")
tiger.comparisons.create(other_obj=cheetah, comparative="stronger")
self.assertQuerysetEqual(cheetah.comparisons.all(), [
"<Comparison: cheetah is faster than tiger>"
])
# Filtering works
self.assertQuerysetEqual(tiger.comparisons.filter(comparative="cooler"), [
"<Comparison: tiger is cooler than cheetah>",
"<Comparison: tiger is cooler than bear>"
])
# Filtering and deleting works
subjective = ["cooler"]
tiger.comparisons.filter(comparative__in=subjective).delete()
self.assertQuerysetEqual(Comparison.objects.all(), [
"<Comparison: cheetah is faster than tiger>",
"<Comparison: tiger is stronger than cheetah>"
])
# If we delete cheetah, Comparisons with cheetah as 'first_obj' will be
# deleted since Animal has an explicit GenericRelation to Comparison
# through first_obj. Comparisons with cheetah as 'other_obj' will not
# be deleted.
from compositekey.tests import ShowSQL
show_sql = ShowSQL("composite_generic_relations")
show_sql.enable = False
with show_sql:
cheetah.delete()
self.assertQuerysetEqual(Comparison.objects.all(), [
"<Comparison: tiger is stronger than None>"
])
def test_generic_relations(self):
# Create the world in 7 lines of code...
lion = Animal.objects.create(common_name="Lion", latin_name="Panthera leo")
platypus = Animal.objects.create(
common_name="Platypus", latin_name="Ornithorhynchus anatinus"
)
eggplant = Vegetable.objects.create(name="Eggplant", is_yucky=True)
bacon = Vegetable.objects.create(name="Bacon", is_yucky=False)
quartz = Mineral.objects.create(name="Quartz", hardness=7)
# Objects with declared GenericRelations can be tagged directly -- the
# API mimics the many-to-many API.
bacon.tags.create(tag="fatty")
bacon.tags.create(tag="salty")
lion.tags.create(tag="yellow")
lion.tags.create(tag="hairy")
platypus.tags.create(tag="fatty")
self.assertQuerysetEqual(lion.tags.all(), [
"<TaggedItem: hairy>",
"<TaggedItem: yellow>"
])
self.assertQuerysetEqual(bacon.tags.all(), [
"<TaggedItem: fatty>",
"<TaggedItem: salty>"
])
# You can easily access the content object like a foreign key.
t = TaggedItem.objects.get(tag="salty")
self.assertEqual(t.content_object, bacon)
# Recall that the Mineral class doesn't have an explicit GenericRelation
# defined. That's OK, because you can create TaggedItems explicitly.
tag1 = TaggedItem.objects.create(content_object=quartz, tag="shiny")
tag2 = TaggedItem.objects.create(content_object=quartz, tag="clearish")
# However, excluding GenericRelations means your lookups have to be a
# bit more explicit.
ctype = ContentType.objects.get_for_model(quartz)
q = TaggedItem.objects.filter(
content_type__pk=ctype.id, object_id=quartz.id
)
self.assertQuerysetEqual(q, [
"<TaggedItem: clearish>",
"<TaggedItem: shiny>"
])
# You can set a generic foreign key in the way you'd expect.
tag1.content_object = platypus
tag1.save()
self.assertQuerysetEqual(platypus.tags.all(), [
"<TaggedItem: fatty>",
"<TaggedItem: shiny>"
])
q = TaggedItem.objects.filter(
content_type__pk=ctype.id, object_id=quartz.id
)
self.assertQuerysetEqual(q, ["<TaggedItem: clearish>"])
# Queries across generic relations respect the content types. Even
# though there are two TaggedItems with a tag of "fatty", this query
# only pulls out the one with the content type related to Animals.
self.assertQuerysetEqual(Animal.objects.order_by('common_name'), [
"<Animal: Lion>",
"<Animal: Platypus>"
])
self.assertQuerysetEqual(Animal.objects.filter(tags__tag='fatty'), [
"<Animal: Platypus>"
])
self.assertQuerysetEqual(Animal.objects.exclude(tags__tag='fatty'), [
"<Animal: Lion>"
])
# If you delete an object with an explicit Generic relation, the related
# objects are deleted when the source object is deleted.
# Original list of tags:
comp_func = lambda obj: (
obj.tag, obj.content_type.model_class(), obj.object_id
)
self.assertQuerysetEqual(TaggedItem.objects.all(), [
('clearish', Mineral, quartz.pk),
('fatty', Animal, platypus.pk),
('fatty', Vegetable, bacon.pk),
('hairy', Animal, lion.pk),
('salty', Vegetable, bacon.pk),
('shiny', Animal, platypus.pk),
('yellow', Animal, lion.pk)
],
comp_func
)
show_sql = ShowSQL("composite_generic_relations")
show_sql.enable = False
with show_sql:
lion.delete()
self.assertQuerysetEqual(TaggedItem.objects.all(), [
('clearish', Mineral, quartz.pk),
('fatty', Animal, platypus.pk),
('fatty', Vegetable, bacon.pk),
('salty', Vegetable, bacon.pk),
('shiny', Animal, platypus.pk)
],
comp_func
)
# If Generic Relation is not explicitly defined, any related objects
# remain after deletion of the source object.
quartz_pk = quartz.pk
quartz.delete()
self.assertQuerysetEqual(TaggedItem.objects.all(), [
('clearish', Mineral, quartz_pk),
('fatty', Animal, platypus.pk),
('fatty', Vegetable, bacon.pk),
('salty', Vegetable, bacon.pk),
('shiny', Animal, platypus.pk)
],
comp_func
)
# If you delete a tag, the objects using the tag are unaffected
# (other than losing a tag)
tag = TaggedItem.objects.order_by("id")[0]
tag.delete()
self.assertQuerysetEqual(bacon.tags.all(), ["<TaggedItem: salty>"])
self.assertQuerysetEqual(TaggedItem.objects.all(), [
('clearish', Mineral, quartz_pk),
('fatty', Animal, platypus.pk),
('salty', Vegetable, bacon.pk),
('shiny', Animal, platypus.pk)
],
comp_func
)
from compositekey.tests import ShowSQL
show_sql = ShowSQL("composite_generic_relations")
show_sql.enable = False
with show_sql:
TaggedItem.objects.filter(tag='fatty').delete()
ctype = ContentType.objects.get_for_model(lion)
self.assertQuerysetEqual(Animal.objects.filter(tags__content_type=ctype), [
"<Animal: Platypus>"
])
self.assertQuerysetEqual(Animal.objects.filter(tags__tag='fatty'), [
"<Animal: Platypus>"
])
self.assertQuerysetEqual(Animal.objects.exclude(tags__tag='fatty'), [
"<Animal: Lion>"
])