django1/tests/regressiontests/aggregation_regress/tests.py

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import datetime
import pickle
from decimal import Decimal
from operator import attrgetter
from django.core.exceptions import FieldError
from django.test import TestCase, Approximate, skipUnlessDBFeature
from django.db.models import Count, Max, Avg, Sum, StdDev, Variance, F
from models import Author, Book, Publisher, Clues, Entries, HardbackBook
class AggregationTests(TestCase):
def assertObjectAttrs(self, obj, **kwargs):
for attr, value in kwargs.iteritems():
self.assertEqual(getattr(obj, attr), value)
def test_aggregates_in_where_clause(self):
"""
Regression test for #12822: DatabaseError: aggregates not allowed in
WHERE clause
Tests that the subselect works and returns results equivalent to a
query with the IDs listed.
Before the corresponding fix for this bug, this test passed in 1.1 and
failed in 1.2-beta (trunk).
"""
qs = Book.objects.values('contact').annotate(Max('id'))
qs = qs.order_by('contact').values_list('id__max', flat=True)
# don't do anything with the queryset (qs) before including it as a
# subquery
books = Book.objects.order_by('id')
qs1 = books.filter(id__in=qs)
qs2 = books.filter(id__in=list(qs))
self.assertEqual(list(qs1), list(qs2))
def test_aggregates_in_where_clause_pre_eval(self):
"""
Regression test for #12822: DatabaseError: aggregates not allowed in
WHERE clause
Same as the above test, but evaluates the queryset for the subquery
before it's used as a subquery.
Before the corresponding fix for this bug, this test failed in both
1.1 and 1.2-beta (trunk).
"""
qs = Book.objects.values('contact').annotate(Max('id'))
qs = qs.order_by('contact').values_list('id__max', flat=True)
# force the queryset (qs) for the subquery to be evaluated in its
# current state
list(qs)
books = Book.objects.order_by('id')
qs1 = books.filter(id__in=qs)
qs2 = books.filter(id__in=list(qs))
self.assertEqual(list(qs1), list(qs2))
@skipUnlessDBFeature('supports_subqueries_in_group_by')
def test_annotate_with_extra(self):
"""
Regression test for #11916: Extra params + aggregation creates
incorrect SQL.
"""
#oracle doesn't support subqueries in group by clause
shortest_book_sql = """
SELECT name
FROM aggregation_regress_book b
WHERE b.publisher_id = aggregation_regress_publisher.id
ORDER BY b.pages
LIMIT 1
"""
# tests that this query does not raise a DatabaseError due to the full
# subselect being (erroneously) added to the GROUP BY parameters
qs = Publisher.objects.extra(select={
'name_of_shortest_book': shortest_book_sql,
}).annotate(total_books=Count('book'))
# force execution of the query
list(qs)
def test_aggregate(self):
# Ordering requests are ignored
self.assertEqual(
Author.objects.order_by("name").aggregate(Avg("age")),
{"age__avg": Approximate(37.444, places=1)}
)
# Implicit ordering is also ignored
self.assertEqual(
Book.objects.aggregate(Sum("pages")),
{"pages__sum": 3703},
)
# Baseline results
self.assertEqual(
Book.objects.aggregate(Sum('pages'), Avg('pages')),
{'pages__sum': 3703, 'pages__avg': Approximate(617.166, places=2)}
)
# Empty values query doesn't affect grouping or results
self.assertEqual(
Book.objects.values().aggregate(Sum('pages'), Avg('pages')),
{'pages__sum': 3703, 'pages__avg': Approximate(617.166, places=2)}
)
# Aggregate overrides extra selected column
self.assertEqual(
Book.objects.extra(select={'price_per_page' : 'price / pages'}).aggregate(Sum('pages')),
{'pages__sum': 3703}
)
def test_annotation(self):
# Annotations get combined with extra select clauses
obj = Book.objects.annotate(mean_auth_age=Avg("authors__age")).extra(select={"manufacture_cost": "price * .5"}).get(pk=2)
self.assertObjectAttrs(obj,
contact_id=3,
id=2,
isbn=u'067232959',
mean_auth_age=45.0,
name='Sams Teach Yourself Django in 24 Hours',
pages=528,
price=Decimal("23.09"),
pubdate=datetime.date(2008, 3, 3),
publisher_id=2,
rating=3.0
)
# Different DB backends return different types for the extra select computation
self.assertTrue(obj.manufacture_cost == 11.545 or obj.manufacture_cost == Decimal('11.545'))
# Order of the annotate/extra in the query doesn't matter
obj = Book.objects.extra(select={'manufacture_cost' : 'price * .5'}).annotate(mean_auth_age=Avg('authors__age')).get(pk=2)
self.assertObjectAttrs(obj,
contact_id=3,
id=2,
isbn=u'067232959',
mean_auth_age=45.0,
name=u'Sams Teach Yourself Django in 24 Hours',
pages=528,
price=Decimal("23.09"),
pubdate=datetime.date(2008, 3, 3),
publisher_id=2,
rating=3.0
)
# Different DB backends return different types for the extra select computation
self.assertTrue(obj.manufacture_cost == 11.545 or obj.manufacture_cost == Decimal('11.545'))
# Values queries can be combined with annotate and extra
obj = Book.objects.annotate(mean_auth_age=Avg('authors__age')).extra(select={'manufacture_cost' : 'price * .5'}).values().get(pk=2)
manufacture_cost = obj['manufacture_cost']
self.assertTrue(manufacture_cost == 11.545 or manufacture_cost == Decimal('11.545'))
del obj['manufacture_cost']
self.assertEqual(obj, {
"contact_id": 3,
"id": 2,
"isbn": u"067232959",
"mean_auth_age": 45.0,
"name": u"Sams Teach Yourself Django in 24 Hours",
"pages": 528,
"price": Decimal("23.09"),
"pubdate": datetime.date(2008, 3, 3),
"publisher_id": 2,
"rating": 3.0,
})
# The order of the (empty) values, annotate and extra clauses doesn't
# matter
obj = Book.objects.values().annotate(mean_auth_age=Avg('authors__age')).extra(select={'manufacture_cost' : 'price * .5'}).get(pk=2)
manufacture_cost = obj['manufacture_cost']
self.assertTrue(manufacture_cost == 11.545 or manufacture_cost == Decimal('11.545'))
del obj['manufacture_cost']
self.assertEqual(obj, {
'contact_id': 3,
'id': 2,
'isbn': u'067232959',
'mean_auth_age': 45.0,
'name': u'Sams Teach Yourself Django in 24 Hours',
'pages': 528,
'price': Decimal("23.09"),
'pubdate': datetime.date(2008, 3, 3),
'publisher_id': 2,
'rating': 3.0
})
# If the annotation precedes the values clause, it won't be included
# unless it is explicitly named
obj = Book.objects.annotate(mean_auth_age=Avg('authors__age')).extra(select={'price_per_page' : 'price / pages'}).values('name').get(pk=1)
self.assertEqual(obj, {
"name": u'The Definitive Guide to Django: Web Development Done Right',
})
obj = Book.objects.annotate(mean_auth_age=Avg('authors__age')).extra(select={'price_per_page' : 'price / pages'}).values('name','mean_auth_age').get(pk=1)
self.assertEqual(obj, {
'mean_auth_age': 34.5,
'name': u'The Definitive Guide to Django: Web Development Done Right',
})
# If an annotation isn't included in the values, it can still be used
# in a filter
qs = Book.objects.annotate(n_authors=Count('authors')).values('name').filter(n_authors__gt=2)
self.assertQuerysetEqual(
qs, [
{"name": u'Python Web Development with Django'}
],
lambda b: b,
)
# The annotations are added to values output if values() precedes
# annotate()
obj = Book.objects.values('name').annotate(mean_auth_age=Avg('authors__age')).extra(select={'price_per_page' : 'price / pages'}).get(pk=1)
self.assertEqual(obj, {
'mean_auth_age': 34.5,
'name': u'The Definitive Guide to Django: Web Development Done Right',
})
# Check that all of the objects are getting counted (allow_nulls) and
# that values respects the amount of objects
self.assertEqual(
len(Author.objects.annotate(Avg('friends__age')).values()),
9
)
# Check that consecutive calls to annotate accumulate in the query
qs = Book.objects.values('price').annotate(oldest=Max('authors__age')).order_by('oldest', 'price').annotate(Max('publisher__num_awards'))
self.assertQuerysetEqual(
qs, [
{'price': Decimal("30"), 'oldest': 35, 'publisher__num_awards__max': 3},
{'price': Decimal("29.69"), 'oldest': 37, 'publisher__num_awards__max': 7},
{'price': Decimal("23.09"), 'oldest': 45, 'publisher__num_awards__max': 1},
{'price': Decimal("75"), 'oldest': 57, 'publisher__num_awards__max': 9},
{'price': Decimal("82.8"), 'oldest': 57, 'publisher__num_awards__max': 7}
],
lambda b: b,
)
def test_aggrate_annotation(self):
# Aggregates can be composed over annotations.
# The return type is derived from the composed aggregate
vals = Book.objects.all().annotate(num_authors=Count('authors__id')).aggregate(Max('pages'), Max('price'), Sum('num_authors'), Avg('num_authors'))
self.assertEqual(vals, {
'num_authors__sum': 10,
'num_authors__avg': Approximate(1.666, places=2),
'pages__max': 1132,
'price__max': Decimal("82.80")
})
def test_field_error(self):
# Bad field requests in aggregates are caught and reported
self.assertRaises(
FieldError,
lambda: Book.objects.all().aggregate(num_authors=Count('foo'))
)
self.assertRaises(
FieldError,
lambda: Book.objects.all().annotate(num_authors=Count('foo'))
)
self.assertRaises(
FieldError,
lambda: Book.objects.all().annotate(num_authors=Count('authors__id')).aggregate(Max('foo'))
)
def test_more(self):
# Old-style count aggregations can be mixed with new-style
self.assertEqual(
Book.objects.annotate(num_authors=Count('authors')).count(),
6
)
# Non-ordinal, non-computed Aggregates over annotations correctly
# inherit the annotation's internal type if the annotation is ordinal
# or computed
vals = Book.objects.annotate(num_authors=Count('authors')).aggregate(Max('num_authors'))
self.assertEqual(
vals,
{'num_authors__max': 3}
)
vals = Publisher.objects.annotate(avg_price=Avg('book__price')).aggregate(Max('avg_price'))
self.assertEqual(
vals,
{'avg_price__max': 75.0}
)
# Aliases are quoted to protected aliases that might be reserved names
vals = Book.objects.aggregate(number=Max('pages'), select=Max('pages'))
self.assertEqual(
vals,
{'number': 1132, 'select': 1132}
)
# Regression for #10064: select_related() plays nice with aggregates
obj = Book.objects.select_related('publisher').annotate(num_authors=Count('authors')).values()[0]
self.assertEqual(obj, {
'contact_id': 8,
'id': 5,
'isbn': u'013790395',
'name': u'Artificial Intelligence: A Modern Approach',
'num_authors': 2,
'pages': 1132,
'price': Decimal("82.8"),
'pubdate': datetime.date(1995, 1, 15),
'publisher_id': 3,
'rating': 4.0,
})
# Regression for #10010: exclude on an aggregate field is correctly
# negated
self.assertEqual(
len(Book.objects.annotate(num_authors=Count('authors'))),
6
)
self.assertEqual(
len(Book.objects.annotate(num_authors=Count('authors')).filter(num_authors__gt=2)),
1
)
self.assertEqual(
len(Book.objects.annotate(num_authors=Count('authors')).exclude(num_authors__gt=2)),
5
)
self.assertEqual(
len(Book.objects.annotate(num_authors=Count('authors')).filter(num_authors__lt=3).exclude(num_authors__lt=2)),
2
)
self.assertEqual(
len(Book.objects.annotate(num_authors=Count('authors')).exclude(num_authors__lt=2).filter(num_authors__lt=3)),
2
)
def test_aggregate_fexpr(self):
# Aggregates can be used with F() expressions
# ... where the F() is pushed into the HAVING clause
qs = Publisher.objects.annotate(num_books=Count('book')).filter(num_books__lt=F('num_awards')/2).order_by('name').values('name','num_books','num_awards')
self.assertQuerysetEqual(
qs, [
{'num_books': 1, 'name': u'Morgan Kaufmann', 'num_awards': 9},
{'num_books': 2, 'name': u'Prentice Hall', 'num_awards': 7}
],
lambda p: p,
)
qs = Publisher.objects.annotate(num_books=Count('book')).exclude(num_books__lt=F('num_awards')/2).order_by('name').values('name','num_books','num_awards')
self.assertQuerysetEqual(
qs, [
{'num_books': 2, 'name': u'Apress', 'num_awards': 3},
{'num_books': 0, 'name': u"Jonno's House of Books", 'num_awards': 0},
{'num_books': 1, 'name': u'Sams', 'num_awards': 1}
],
lambda p: p,
)
# ... and where the F() references an aggregate
qs = Publisher.objects.annotate(num_books=Count('book')).filter(num_awards__gt=2*F('num_books')).order_by('name').values('name','num_books','num_awards')
self.assertQuerysetEqual(
qs, [
{'num_books': 1, 'name': u'Morgan Kaufmann', 'num_awards': 9},
{'num_books': 2, 'name': u'Prentice Hall', 'num_awards': 7}
],
lambda p: p,
)
qs = Publisher.objects.annotate(num_books=Count('book')).exclude(num_books__lt=F('num_awards')/2).order_by('name').values('name','num_books','num_awards')
self.assertQuerysetEqual(
qs, [
{'num_books': 2, 'name': u'Apress', 'num_awards': 3},
{'num_books': 0, 'name': u"Jonno's House of Books", 'num_awards': 0},
{'num_books': 1, 'name': u'Sams', 'num_awards': 1}
],
lambda p: p,
)
def test_db_col_table(self):
# Tests on fields with non-default table and column names.
qs = Clues.objects.values('EntryID__Entry').annotate(Appearances=Count('EntryID'), Distinct_Clues=Count('Clue', distinct=True))
self.assertQuerysetEqual(qs, [])
qs = Entries.objects.annotate(clue_count=Count('clues__ID'))
self.assertQuerysetEqual(qs, [])
def test_empty(self):
# Regression for #10089: Check handling of empty result sets with
# aggregates
self.assertEqual(
Book.objects.filter(id__in=[]).count(),
0
)
vals = Book.objects.filter(id__in=[]).aggregate(num_authors=Count('authors'), avg_authors=Avg('authors'), max_authors=Max('authors'), max_price=Max('price'), max_rating=Max('rating'))
self.assertEqual(
vals,
{'max_authors': None, 'max_rating': None, 'num_authors': 0, 'avg_authors': None, 'max_price': None}
)
qs = Publisher.objects.filter(pk=5).annotate(num_authors=Count('book__authors'), avg_authors=Avg('book__authors'), max_authors=Max('book__authors'), max_price=Max('book__price'), max_rating=Max('book__rating')).values()
self.assertQuerysetEqual(
qs, [
{'max_authors': None, 'name': u"Jonno's House of Books", 'num_awards': 0, 'max_price': None, 'num_authors': 0, 'max_rating': None, 'id': 5, 'avg_authors': None}
],
lambda p: p
)
def test_more_more(self):
# Regression for #10113 - Fields mentioned in order_by() must be
# included in the GROUP BY. This only becomes a problem when the
# order_by introduces a new join.
self.assertQuerysetEqual(
Book.objects.annotate(num_authors=Count('authors')).order_by('publisher__name', 'name'), [
"Practical Django Projects",
"The Definitive Guide to Django: Web Development Done Right",
"Paradigms of Artificial Intelligence Programming: Case Studies in Common Lisp",
"Artificial Intelligence: A Modern Approach",
"Python Web Development with Django",
"Sams Teach Yourself Django in 24 Hours",
],
lambda b: b.name
)
# Regression for #10127 - Empty select_related() works with annotate
qs = Book.objects.filter(rating__lt=4.5).select_related().annotate(Avg('authors__age'))
self.assertQuerysetEqual(
qs, [
(u'Artificial Intelligence: A Modern Approach', 51.5, u'Prentice Hall', u'Peter Norvig'),
(u'Practical Django Projects', 29.0, u'Apress', u'James Bennett'),
(u'Python Web Development with Django', Approximate(30.333, places=2), u'Prentice Hall', u'Jeffrey Forcier'),
(u'Sams Teach Yourself Django in 24 Hours', 45.0, u'Sams', u'Brad Dayley')
],
lambda b: (b.name, b.authors__age__avg, b.publisher.name, b.contact.name)
)
# Regression for #10132 - If the values() clause only mentioned extra
# (select=) columns, those columns are used for grouping
qs = Book.objects.extra(select={'pub':'publisher_id'}).values('pub').annotate(Count('id')).order_by('pub')
self.assertQuerysetEqual(
qs, [
{'pub': 1, 'id__count': 2},
{'pub': 2, 'id__count': 1},
{'pub': 3, 'id__count': 2},
{'pub': 4, 'id__count': 1}
],
lambda b: b
)
qs = Book.objects.extra(select={'pub':'publisher_id', 'foo':'pages'}).values('pub').annotate(Count('id')).order_by('pub')
self.assertQuerysetEqual(
qs, [
{'pub': 1, 'id__count': 2},
{'pub': 2, 'id__count': 1},
{'pub': 3, 'id__count': 2},
{'pub': 4, 'id__count': 1}
],
lambda b: b
)
# Regression for #10182 - Queries with aggregate calls are correctly
# realiased when used in a subquery
ids = Book.objects.filter(pages__gt=100).annotate(n_authors=Count('authors')).filter(n_authors__gt=2).order_by('n_authors')
self.assertQuerysetEqual(
Book.objects.filter(id__in=ids), [
"Python Web Development with Django",
],
lambda b: b.name
)
def test_duplicate_alias(self):
# Regression for #11256 - duplicating a default alias raises ValueError.
self.assertRaises(ValueError, Book.objects.all().annotate, Avg('authors__age'), authors__age__avg=Avg('authors__age'))
def test_field_name_conflict(self):
# Regression for #11256 - providing an aggregate name that conflicts with a field name on the model raises ValueError
self.assertRaises(ValueError, Author.objects.annotate, age=Avg('friends__age'))
def test_m2m_name_conflict(self):
# Regression for #11256 - providing an aggregate name that conflicts with an m2m name on the model raises ValueError
self.assertRaises(ValueError, Author.objects.annotate, friends=Count('friends'))
def test_reverse_relation_name_conflict(self):
# Regression for #11256 - providing an aggregate name that conflicts with a reverse-related name on the model raises ValueError
self.assertRaises(ValueError, Author.objects.annotate, book_contact_set=Avg('friends__age'))
def test_pickle(self):
# Regression for #10197 -- Queries with aggregates can be pickled.
# First check that pickling is possible at all. No crash = success
qs = Book.objects.annotate(num_authors=Count('authors'))
pickle.dumps(qs)
# Then check that the round trip works.
query = qs.query.get_compiler(qs.db).as_sql()[0]
qs2 = pickle.loads(pickle.dumps(qs))
self.assertEqual(
qs2.query.get_compiler(qs2.db).as_sql()[0],
query,
)
def test_more_more_more(self):
# Regression for #10199 - Aggregate calls clone the original query so
# the original query can still be used
books = Book.objects.all()
books.aggregate(Avg("authors__age"))
self.assertQuerysetEqual(
books.all(), [
u'Artificial Intelligence: A Modern Approach',
u'Paradigms of Artificial Intelligence Programming: Case Studies in Common Lisp',
u'Practical Django Projects',
u'Python Web Development with Django',
u'Sams Teach Yourself Django in 24 Hours',
u'The Definitive Guide to Django: Web Development Done Right'
],
lambda b: b.name
)
# Regression for #10248 - Annotations work with DateQuerySets
qs = Book.objects.annotate(num_authors=Count('authors')).filter(num_authors=2).dates('pubdate', 'day')
self.assertQuerysetEqual(
qs, [
datetime.datetime(1995, 1, 15, 0, 0),
datetime.datetime(2007, 12, 6, 0, 0)
],
lambda b: b
)
# Regression for #10290 - extra selects with parameters can be used for
# grouping.
qs = Book.objects.annotate(mean_auth_age=Avg('authors__age')).extra(select={'sheets' : '(pages + %s) / %s'}, select_params=[1, 2]).order_by('sheets').values('sheets')
self.assertQuerysetEqual(
qs, [
150,
175,
224,
264,
473,
566
],
lambda b: int(b["sheets"])
)
# Regression for 10425 - annotations don't get in the way of a count()
# clause
self.assertEqual(
Book.objects.values('publisher').annotate(Count('publisher')).count(),
4
)
self.assertEqual(
Book.objects.annotate(Count('publisher')).values('publisher').count(),
6
)
publishers = Publisher.objects.filter(id__in=[1, 2])
self.assertQuerysetEqual(
publishers, [
"Apress",
"Sams"
],
lambda p: p.name
)
publishers = publishers.annotate(n_books=Count("book"))
self.assertEqual(
publishers[0].n_books,
2
)
self.assertQuerysetEqual(
publishers, [
"Apress",
"Sams",
],
lambda p: p.name
)
books = Book.objects.filter(publisher__in=publishers)
self.assertQuerysetEqual(
books, [
"Practical Django Projects",
"Sams Teach Yourself Django in 24 Hours",
"The Definitive Guide to Django: Web Development Done Right",
],
lambda b: b.name
)
self.assertQuerysetEqual(
publishers, [
"Apress",
"Sams",
],
lambda p: p.name
)
# Regression for 10666 - inherited fields work with annotations and
# aggregations
self.assertEqual(
HardbackBook.objects.aggregate(n_pages=Sum('book_ptr__pages')),
{'n_pages': 2078}
)
self.assertEqual(
HardbackBook.objects.aggregate(n_pages=Sum('pages')),
{'n_pages': 2078},
)
qs = HardbackBook.objects.annotate(n_authors=Count('book_ptr__authors')).values('name', 'n_authors')
self.assertQuerysetEqual(
qs, [
{'n_authors': 2, 'name': u'Artificial Intelligence: A Modern Approach'},
{'n_authors': 1, 'name': u'Paradigms of Artificial Intelligence Programming: Case Studies in Common Lisp'}
],
lambda h: h
)
qs = HardbackBook.objects.annotate(n_authors=Count('authors')).values('name', 'n_authors')
self.assertQuerysetEqual(
qs, [
{'n_authors': 2, 'name': u'Artificial Intelligence: A Modern Approach'},
{'n_authors': 1, 'name': u'Paradigms of Artificial Intelligence Programming: Case Studies in Common Lisp'}
],
lambda h: h,
)
# Regression for #10766 - Shouldn't be able to reference an aggregate
# fields in an an aggregate() call.
self.assertRaises(
FieldError,
lambda: Book.objects.annotate(mean_age=Avg('authors__age')).annotate(Avg('mean_age'))
)
def test_empty_filter_count(self):
self.assertEqual(
Author.objects.filter(id__in=[]).annotate(Count("friends")).count(),
0
)
def test_empty_filter_aggregate(self):
self.assertEqual(
Author.objects.filter(id__in=[]).annotate(Count("friends")).aggregate(Count("pk")),
{"pk__count": None}
)
def test_annotate_and_join(self):
self.assertEqual(
Author.objects.annotate(c=Count("friends__name")).exclude(friends__name="Joe").count(),
Author.objects.count()
)
def test_f_expression_annotation(self):
# Books with less than 200 pages per author.
qs = Book.objects.values("name").annotate(
n_authors=Count("authors")
).filter(
pages__lt=F("n_authors") * 200
).values_list("pk")
self.assertQuerysetEqual(
Book.objects.filter(pk__in=qs), [
"Python Web Development with Django"
],
attrgetter("name")
)
@skipUnlessDBFeature('supports_stddev')
def test_stddev(self):
self.assertEqual(
Book.objects.aggregate(StdDev('pages')),
{'pages__stddev': Approximate(311.46, 1)}
)
self.assertEqual(
Book.objects.aggregate(StdDev('rating')),
{'rating__stddev': Approximate(0.60, 1)}
)
self.assertEqual(
Book.objects.aggregate(StdDev('price')),
{'price__stddev': Approximate(24.16, 2)}
)
self.assertEqual(
Book.objects.aggregate(StdDev('pages', sample=True)),
{'pages__stddev': Approximate(341.19, 2)}
)
self.assertEqual(
Book.objects.aggregate(StdDev('rating', sample=True)),
{'rating__stddev': Approximate(0.66, 2)}
)
self.assertEqual(
Book.objects.aggregate(StdDev('price', sample=True)),
{'price__stddev': Approximate(26.46, 1)}
)
self.assertEqual(
Book.objects.aggregate(Variance('pages')),
{'pages__variance': Approximate(97010.80, 1)}
)
self.assertEqual(
Book.objects.aggregate(Variance('rating')),
{'rating__variance': Approximate(0.36, 1)}
)
self.assertEqual(
Book.objects.aggregate(Variance('price')),
{'price__variance': Approximate(583.77, 1)}
)
self.assertEqual(
Book.objects.aggregate(Variance('pages', sample=True)),
{'pages__variance': Approximate(116412.96, 1)}
)
self.assertEqual(
Book.objects.aggregate(Variance('rating', sample=True)),
{'rating__variance': Approximate(0.44, 2)}
)
self.assertEqual(
Book.objects.aggregate(Variance('price', sample=True)),
{'price__variance': Approximate(700.53, 2)}
)