Django测试未获取模型对象 [英] Django Test Not Getting Model Object

问题描述

我只是在摸索Django中的测试表面。这是我的测试代码，位于 tests.py 内：

I am just scratching the surface of testing in Django. Here is my testing code, inside tests.py:

class AdvertisingTests( TestCase ):

    def test_get_ad( self ):
        '''
        Test if the get ad feature is working, should always load an ad
        '''
        url = reverse('advertising:get_ad')
        response = self.client.get( url )
        self.assertEqual(response.status_code, 200)

此测试只是对应该返回广告的视图的基本测试。这是查看代码：

This test is just a basic test of a view that should return an Ad. Here is the view code:

from .models import Ad, Impression

def get_ad(request):
    FirstAd = Ad.objects.first()

    # +1 impression
    Impression.objects.create(ad = FirstAd)

    import json
    data = { 'url': FirstAd.url, 'image_url': FirstAd.image.url, 'title': FirstAd.title, 'desc': FirstAd.desc }
    json_data = json.dumps( data )
    return HttpResponse(json_data, content_type='application/json')

I在heroku本地环境中工作，所以我运行如下测试：
heroku local：运行python manage.py测试广告

I am working in a heroku local environment, so I run the tests like this: heroku local:run python manage.py test advertising

此测试失败，来自 Impression.objects.create（ad = FirstAd）行：

ValueError：无法分配无： Impression.ad不允许空
值。

ValueError: Cannot assign None: "Impression.ad" does not allow null values.

告诉我的是 FirstAd 对象一片空白。好的，这样我就可以结束本地shell了： heroku local：run python manage.py shell 进行仔细检查。复制该代码没有错误：

What that tells me is that the FirstAd object is null. OK so I wind up the local shell like this: heroku local:run python manage.py shell to double check. Replicating that code there are no errors:

In [2]: from advertising.models import Ad, Impression

In [3]: print Ad.objects.first()
Flamingo T-Shirt Corporation

In [4]: FirstAd = Ad.objects.first()

In [5]: Impression.objects.create(ad = FirstAd)
Out[5]: <Impression: Impression object>

In [6]: exit()

所以我有点有点卡住。看来测试人员正在访问一个空的数据库。这是测试套件的正确功能吗？

So I am a little bit stuck. It seems like the tester is accessing an empty database. Is this the correct and desired functionality of the testing suite?

谢谢！

更新

好的，这一切都很正常，我应该知道这一点。我需要做的就是将setUp函数添加到测试类中以初始化数据。像这样：

OK so all this is normal, I should have known that. Adding the setUp function to my test class to initialise data is what I needed to do. Like this:

from django.core.files.uploadedfile import SimpleUploadedFile

def setUp(self):
    test_user = User.objects.create_user(username='testuser', password='12345')

    this_path = os.path.abspath(os.path.dirname(__file__))
    banner_image = os.path.join(this_path, "static/advertising/images/pic01.jpg")
    mobile_image = os.path.join(this_path, "static/advertising/images/pic02.jpg")

    Ad.objects.create(
        title = "Test Title",
        desc = "Test Description",
        image = SimpleUploadedFile(name='test_image.jpg', content=open(banner_image, 'rb').read(), content_type='image/jpeg'),
        mobile_image = SimpleUploadedFile(name='test_image.jpg', content=open(mobile_image, 'rb').read(), content_type='image/jpeg'),
        url = "https://www.jefferythewind.com",
        user = test_user
    )

推荐答案

Django te sts创建空的临时数据库，请参见文档 ，将在测试后销毁。

Django tests create empty temporaty database see docs, which will be destroyed after tests.

要使用数据预先填充测试数据库，可以使用 setUp 方法：

To prepopulate testing DB with data you can use setUp method:

class AdvertisingTests(TestCase):
    def setUp(self):
        Ad.objects.create(name="myAd")

也可以使用夹具。

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