问题
Following the tutorial at djangoproject, I have tried to have urls.py filter out the polls with no choices with the urlpattern below.
urlpatterns = patterns('',
url(r'^$',
ListView.as_view(
queryset=Poll.objects.filter(choice__choice_text__isnull=False) \
.filter(pub_date__lte=timezone.now) \
.order_by('-pub_date')[:5],
context_object_name='latest_polls',
template_name='polls/index.html'),
name='index'),
url(r'^(?P<pk>\d+)/$',
DetailView.as_view(
queryset=Poll.objects.filter(choice__choice_text__isnull=False) \
.filter(pub_date__lte=timezone.now),
model=Poll,
template_name='polls/detail.html'),
name='detail'),
url(r'^(?P<pk>\d+)/results/$',
DetailView.as_view(
queryset=Poll.objects.filter(choice__choice_text__isnull=False) \
.filter(pub_date__lte=timezone.now),
model=Poll,
template_name='polls/results.html'),
name='results'),
url(r'^(?P<poll_id>\d+)/vote/$', 'polls.views.vote', name='vote'),
)
However, when I run the tests from the tutorial, an assertion error occurs for each test that creates a past_poll, similar to the error below.
AssertionError: Lists differ: [] != ['<Poll: Past poll.>']
Second list contains 1 additional elements.
First extra element 0:
<Poll: Past poll.>
- []
+ ['<Poll: Past poll.>']
Before I changed the queryset to filter out all polls w/o choices the tests didn't fail. I have tested the filter in the shell and it works and running the app on the django server also doesn't seem to have any problems. What is going wrong?
Here is the tests.py file that I used
import datetime
from django.utils import timezone
from django.core.urlresolvers import reverse
from django.test import TestCase
from polls.models import Poll
def create_poll(question, days):
"""
Creates a poll with the given `question` published the given number of
`days` offset to now (negative for polls published in the past,
positive for polls that have yet to be published).
"""
return Poll.objects.create(question=question,
pub_date=timezone.now() + datetime.timedelta(days=days))
class PollIndexDetailTests(TestCase):
def test_detail_view_with_a_future_poll(self):
"""
The detail view of a poll with a pub_date in the future should
return a 404 not found.
"""
future_poll = create_poll(question='Future poll.', days=5)
response = self.client.get(reverse('polls:detail', args=(future_poll.id,)))
self.assertEqual(response.status_code, 404)
def test_detail_view_with_a_past_poll(self):
"""
The detail view of a poll with a pub_date in the past should display
the poll's question.
"""
past_poll = create_poll(question='Past Poll.', days=-5)
response = self.client.get(reverse('polls:detail', args=(past_poll.id,)))
self.assertContains(response, past_poll.question, status_code=200)
class PollIndexResultsTests(TestCase):
def test_results_view_with_a_future_poll(self):
"""
The results view of a poll with a pub_date in the future should
return a 404 not found.
"""
future_poll = create_poll(question='Future poll.', days=5)
response = self.client.get(reverse('polls:results', args=(future_poll.id,)))
self.assertEqual(response.status_code, 404)
def test_results_view_with_a_past_poll(self):
"""
The results view of a poll with a pub_date in the past should display
the poll's question.
"""
past_poll = create_poll(question='Past Poll.', days=-5)
response = self.client.get(reverse('polls:results', args=(past_poll.id,)))
self.assertContains(response, past_poll.question, status_code=200)
class PollViewTests(TestCase):
def test_index_view_with_no_polls(self):
"""
If no polls exist, an appropriate message should be displayed.
"""
response = self.client.get(reverse('polls:index'))
self.assertEqual(response.status_code, 200)
self.assertContains(response, "No polls are available.")
self.assertQuerysetEqual(response.context['latest_polls'], [])
def test_index_view_with_a_past_poll(self):
"""
Polls with a pub_date in the past should be displayed on the index page.
"""
create_poll(question="Past poll.", days=-30)
response = self.client.get(reverse('polls:index'))
self.assertQuerysetEqual(
response.context['latest_polls'],
['<Poll: Past poll.>']
)
def test_index_view_with_a_future_poll(self):
"""
Polls with a pub_date in the future should not be displayed on the
index page.
"""
create_poll(question="Future poll.", days=30)
response = self.client.get(reverse('polls:index'))
self.assertContains(response, "No polls are available.", status_code=200)
self.assertQuerysetEqual(response.context['latest_polls'], [])
def test_index_view_with_future_poll_and_past_poll(self):
"""
Even if both past and future polls exist, only past polls should be
displayed.
"""
create_poll(question="Past poll.", days=-30)
create_poll(question="Future poll.", days=30)
response = self.client.get(reverse('polls:index'))
self.assertQuerysetEqual(
response.context['latest_polls'],
['<Poll: Past poll.>']
)
def test_index_view_with_two_past_polls(self):
"""
The polls index page may display multiple polls.
"""
create_poll(question="Past poll 1.", days=-30)
create_poll(question="Past poll 2.", days=-5)
response = self.client.get(reverse('polls:index'))
self.assertQuerysetEqual(
response.context['latest_polls'],
['<Poll: Past poll 2.>', '<Poll: Past poll 1.>']
)
class PollMethodTests(TestCase):
def test_was_published_recently_with_future_poll(self):
"""
was_published_recently() should return False for polls whose
pub_date is in the future
"""
future_poll = Poll(pub_date=timezone.now() + datetime.timedelta(days=30))
self.assertEqual(future_poll.was_published_recently(), False)
def test_was_published_recently_with_old_poll(self):
"""
was_published_recently() should return False for polls whose pub_date
is older than 1 day
"""
old_poll = Poll(pub_date=timezone.now() - datetime.timedelta(days=30))
self.assertEqual(old_poll.was_published_recently(), False)
def test_was_published_recently_with_recent_poll(self):
"""
was_published_recently() should return True for polls whose pub_date
is within the last day
"""
recent_poll = Poll(pub_date=timezone.now() - datetime.timedelta(hours=1))
self.assertEqual(recent_poll.was_published_recently(), True)
回答1:
I think the problem is, that on the test, you're creating a brand new poll, without any choices yet. And in the detail-view you're filtering this polls out. So it's returning nothing, and so the test fails.
You could additionally create some choices for the poll you just created on the past_test so this polls pass the filtering.
Something like:
...
past_poll = create_poll(question='Past Poll.', days=-5)
past_poll.choice_set.create(choice_text='Choice 1', votes=0)
past_poll.choice_set.create(choice_text='Choice 2', votes=0)
...
来源：https://stackoverflow.com/questions/15799905/adding-extra-filter-to-polls-urls-py-causes-tests-to-fail