Tests aggregation DurationField

Classe Publisher

class Publisher(models.Model):
    name = models.CharField(max_length=255)
    num_awards = models.IntegerField()
    duration = models.DurationField(blank=True, null=True)

    def __str__(self):
        return self.name

class AggregateTestCase(TestCase)

import datetime
import re
from decimal import Decimal

from django.core.exceptions import FieldError
from django.db import connection
from django.db.models import (
    Avg, Case, Count, DecimalField, DurationField, Exists, F, FloatField, Func,
    IntegerField, Max, Min, OuterRef, Subquery, Sum, Value, When,
)
from django.db.models.functions import Coalesce
from django.test import TestCase
from django.test.testcases import skipUnlessDBFeature
from django.test.utils import Approximate, CaptureQueriesContext
from django.utils import timezone

from .models import Author, Book, Publisher, Store


class AggregateTestCase(TestCase):

    @classmethod
    def setUpTestData(cls):
        cls.a1 = Author.objects.create(name='Adrian Holovaty', age=34)
        cls.a2 = Author.objects.create(name='Jacob Kaplan-Moss', age=35)
        cls.a3 = Author.objects.create(name='Brad Dayley', age=45)
        cls.a4 = Author.objects.create(name='James Bennett', age=29)
        cls.a5 = Author.objects.create(name='Jeffrey Forcier', age=37)
        cls.a6 = Author.objects.create(name='Paul Bissex', age=29)
        cls.a7 = Author.objects.create(name='Wesley J. Chun', age=25)
        cls.a8 = Author.objects.create(name='Peter Norvig', age=57)
        cls.a9 = Author.objects.create(name='Stuart Russell', age=46)
        cls.a1.friends.add(cls.a2, cls.a4)
        cls.a2.friends.add(cls.a1, cls.a7)
        cls.a4.friends.add(cls.a1)
        cls.a5.friends.add(cls.a6, cls.a7)
        cls.a6.friends.add(cls.a5, cls.a7)
        cls.a7.friends.add(cls.a2, cls.a5, cls.a6)
        cls.a8.friends.add(cls.a9)
        cls.a9.friends.add(cls.a8)

        cls.p1 = Publisher.objects.create(name='Apress', num_awards=3, duration=datetime.timedelta(days=1))
        cls.p2 = Publisher.objects.create(name='Sams', num_awards=1, duration=datetime.timedelta(days=2))
        cls.p3 = Publisher.objects.create(name='Prentice Hall', num_awards=7)
        cls.p4 = Publisher.objects.create(name='Morgan Kaufmann', num_awards=9)
        cls.p5 = Publisher.objects.create(name="Jonno's House of Books", num_awards=0)

test_avg_duration_field

def test_avg_duration_field(self):
    # Explicit `output_field`.
    self.assertEqual(
        Publisher.objects.aggregate(Avg('duration', output_field=DurationField())),
        {'duration__avg': datetime.timedelta(days=1, hours=12)}
    )
    # Implicit `output_field`.
    self.assertEqual(
        Publisher.objects.aggregate(Avg('duration')),
        {'duration__avg': datetime.timedelta(days=1, hours=12)}
    )

test_sum_duration_field

def test_sum_duration_field(self):
    self.assertEqual(
        Publisher.objects.aggregate(Sum('duration', output_field=DurationField())),
        {'duration__sum': datetime.timedelta(days=3)}
    )