如何在Django中测试auto_now_add

Question

我有django 1.11应用程序，我想为我的解决方案编写单元测试。

我想测试注册日期功能。

model.py：

class User(models.Model):
    first_name = models.CharField(max_length=30)
    last_name = models.CharField(max_length=30)
    registration_date = models.DateTimeField(auto_now_add=True)

    def get_registration_date(self):
        return self.registration_date

我还在模型工厂中使用django-boy：factory.py

  class UserFactory(factory.DjangoModelFactory):
        class Meta:
            model = models.User
        first_name = 'This is first name'
        last_name = 'This is last name'
        registration_date = timezone.now()

test.py

def test_get_registration_date(self):
    user = factories.UserFactory.create()
    self.assertEqual(user.get_registration_date(), timezone.now())

问题是我接受了AssertionError：

AssertionError: datetime.datetime(2018, 4, 17, 9, 39, 36, 707927, tzinfo=<UTC>) != datetime.datetime(2018, 4, 17, 9, 39, 36, 708069, tzinfo=<UTC>)

Answer 1

您可以使用mock：

import pytz
from unittest import mock

def test_get_registration_date(self):
    mocked = datetime.datetime(2018, 4, 4, 0, 0, 0, tzinfo=pytz.utc)
    with mock.patch('django.utils.timezone.now', mock.Mock(return_value=mocked))
        user = factories.UserFactory.create()
        self.assertEqual(user.get_registration_date(), mocked)

Answer 2

您可以使用包装冷冻枪。https://github.com/splec/freezegun修补了 datetime.now()。

from freezegun import freeze_time
...
    @freeze_time("2017-06-23 07:28:00")
    def test_get_registration_date(self):
        user = factories.UserFactory.create()
        self.assertEqual(
            datetime.strftime(user.get_registration_date(), "%Y-%m-%d %H:%M:%S")
            "2017-06-23 07:28:00"
        )

Answer 3

使用with 的通用方法with withFactory BoyDjangoDateTimeauto_now_add=True

1. 引入自定义DjangoFactory，使用arg_fake_time来冻结对象创建期间的时间

from contextlib import suppress
from factory.django import DjangoModelFactory
from freezegun import freeze_time
from functools import partial

class CustomDjangoModelFactory(DjangoModelFactory):

    @classmethod
    def create(cls, _fake_time=None, **kwargs):
        wrapper = partial(freeze_time, time_to_freeze=_fake_time) if _fake_time else suppress
        with wrapper(_fake_time):
            return super().create(**kwargs)

2. 添加/更改您的工厂基于CustomDjangoModelFactory

import factory
from django.db import models

class MyModel(models.Model):
    name = models.CharField(max_length=255)
    created = models.DateTimeField(auto_now_add=True)

class MyModelFactory(CustomDjangoModelFactory):
    name = factory.Sequence(lambda n: "Model No. %03d" % n)

    class Meta:
        model = MyModel

3. 使用_fake_time或不使用它

my_model1 = MyModelFactory(name='first', _fake_time='2020-12-1')
my_model2 = MyModelFactory(name='second', _fake_time=datetime(2020, 11, 30))
my_model3 = MyModelFactory(name='third')