Django Tutorial 4
In this part of my Django tutorial series we’ll focus on Generic Views and Automated Testing. Through testing we can quickly check how are site is operating after each change. You can also simulate how the site will interact with a user depending upon an unlimited number of randomized inputs. With a little work up front you will save yourself from numerous future headaches.
All of the code follows the video below.
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Code & Transcript
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# ---------- /polls/urls.py ---------- # 1 Generic views are normally used from the beginning # and they help you avoid having to write a lot # of custom code from django.conf.urls import url from . import views app_name = 'polls' # 1 We'll change the urlpatterns urlpatterns = [ url(r'^$', views.IndexView.as_view(), name='index'), url(r'^(?P<pk>[0-9]+)/$', views.DetailView.as_view(), name='detail'), url(r'^(?P<pk>[0-9]+)/results/$', views.ResultsView.as_view(), name='results'), url(r'^(?P<question_id>[0-9]+)/vote/$', views.vote, name='vote'), ] # 1 Now remove our index, detail and results views in polls/views.py ''' urlpatterns = [ url(r'^$', views.index, name='index'), url(r'^(?P<question_id>[0-9]+)/$', views.detail, name='detail'), url(r'^(?P<question_id>[0-9]+)/results/$', views.results, name='results'), url(r'^(?P<question_id>[0-9]+)/vote/$', views.vote, name='vote'), ] ''' # ---------- /polls/views.py ---------- from django.http import HttpResponse from .models import Question, Choice from django.shortcuts import render from django.shortcuts import get_object_or_404 from django.http import HttpResponseRedirect from django.urls import reverse # 2 Add the generic module from django.views import generic # 8 Import so we can get time information from django.utils import timezone # 2 The ListView displays your list of questions being # latest_question_list class IndexView(generic.ListView): template_name = 'polls/index.html' # 2 This defines the question list we want to use context_object_name = 'latest_question_list' # 8 Replace get_queryset and don't return questions # published in the future ''' def get_queryset(self): # 2 Return the last 5 questions entered return Question.objects.order_by('-pub_date')[:5] ''' def get_queryset(self): # 8 Return only questions with a pub_date less than # or equal to now return Question.objects.filter( pub_date__lte=timezone.now() ).order_by('-pub_date')[:5] # 8 Add Choices to the Admin in admin.py # 2 The DetailView displays the details on your object # being the Question model # 2 The generic view expects the pk (Primary Key) value # from the URL to be called pk as we set in polls/urls.py class DetailView(generic.DetailView): model = Question # 2 Define the template to use with this data template_name = 'polls/detail.html' # 12 Exclude questions that are not published yet def get_queryset(self): return Question.objects.filter(pub_date__lte=timezone.now()) # 12 Add tests in polls/tests.py # 2 class ResultsView(generic.DetailView): model = Question template_name = 'polls/results.html' # 2 Remove these functions ''' def index(request): latest_question_list = Question.objects.order_by('-pub_date')[:5] context = { 'latest_question_list': latest_question_list, } return render(request, 'polls/index.html', context) def detail(request, question_id): question = get_object_or_404(Question, pk=question_id) return render(request, 'polls/detail.html', {'question': question}) def results(request, question_id): question = get_object_or_404(Question, pk=question_id) return render(request, 'polls/results.html', {'question': question}) ''' # 2 Vote stays the same def vote(request, question_id): question = get_object_or_404(Question, pk=question_id) try: selected_choice = question.choice_set.get(pk=request.POST['choice']) except(KeyError, Choice.DoesNotExist): return render(request, 'polls/detail.html', { 'question': question, 'error_message': "You didn't select a choice" }) else: selected_choice.votes += 1 selected_choice.save() return HttpResponseRedirect(reverse('polls:results', args=(question.id,))) # 3 Now we will explore automated testing. You can either # check your code by entering values randomly (and miss # a bunch of errors), or you can automate the process. # 3 We'll now explore a bug in the was_published_recently() function # in polls/models.py in the shell : python3 manage.py shell # 3 Create a Question with a pub_date in the future ''' import datetime from django.utils import timezone from polls.models import Question future_question = Question(pub_date=timezone.now() + datetime.timedelta(days=30)) future_question.was_published_recently() Returns true even though that doesn't make sense ''' # 3 Open the file called tests.py # ---------- /polls/tests.py ---------- from django.test import TestCase # 4 Import your needed modules import datetime from django.utils import timezone from django.test import TestCase from .models import Question # 4 TestCase runs tests without effecting your data # by creating a temporary database for testing class QuestionMethodTests(TestCase): # 4 Put the code used in the shell here # Start the method name with test def test_was_published_recently_with_future_question(self): # 4 Create a time 30 days in the future time = timezone.now() + datetime.timedelta(days=30) # 4 Create a question using the future time future_question = Question(pub_date=time) # 4 Check to see if the output is False like we expect self.assertIs(future_question.was_published_recently(), False) # 4 Run the test in the terminal # python3 manage.py test polls # You'll see that the test failed # 4 Fix the bug in models.py # 6 Return false if pub_date is older then 1 day def test_was_published_recently_with_old_question(self): # Should return false if pub_date is older then 1 day time = timezone.now() - datetime.timedelta(days=30) old_question = Question(pub_date=time) self.assertIs(old_question.was_published_recently(), False) # 6 Return True if published within the last day def test_was_published_recently_with_recent_question(self): time = timezone.now() - datetime.timedelta(hours=1) recent_question = Question(pub_date=time) self.assertIs(recent_question.was_published_recently(), True) # 6 Test with : python3 manage.py test polls # 7 We can simulate user interaction at the view level in the shell # python3 manage.py shell ''' # This allows us access variable values in our templates # We will be using our real database here from django.test.utils import setup_test_environment setup_test_environment() # Create the client that we'll use to run our app from django.test import Client client = Client() # Get the status code from localhost:8000/ response = client.get('/') response.status_code # Get the status code for localhost:8000/polls/ from django.urls import reverse response = client.get(reverse('polls:index')) response.status_code # Get the HTML content response.content # Get the value of latest_question_list response.context['latest_question_list'] ''' # 7 Let's update polls/views.py so it doesn't show # questions published in the future # 10 Create a function that creates questions at # a specified date def create_question(question_text, days): time = timezone.now() + datetime.timedelta(days=days) return Question.objects.create(question_text=question_text, pub_date=time) # 10 Add more question tests class QuestionViewTests(TestCase): # 10 Test to see what happens if there are no questions def test_index_view_with_no_questions(self): # Get the client response = self.client.get(reverse('polls:index')) # Check the status code self.assertEqual(response.status_code, 200) # Verify that response contains this string self.assertContains(response, "No polls are available.") # Check if latest_question_list is empty self.assertQuerysetEqual(response.context['latest_question_list'], []) # 10 Make sure questions with a pub_date in past are shown def test_index_view_with_a_past_question(self): # Create sample question create_question(question_text="Past question.", days=-30) # Get client response = self.client.get(reverse('polls:index')) # Verify that the question shows self.assertQuerysetEqual( response.context['latest_question_list'], ['<Question: Past question.>'] ) # 10 Make sure questions with future pub_date don't show def test_index_view_with_a_future_question(self): # Create question create_question(question_text="Future question.", days=30) # Get client response = self.client.get(reverse('polls:index')) # Verify response contains text self.assertContains(response, "No polls are available.") # Verify that latest_question_list is empty self.assertQuerysetEqual(response.context['latest_question_list'], []) # 10 Verify that if past and future questions exist that only # past show def test_index_view_with_future_question_and_past_question(self): # Create questions create_question(question_text="Past question.", days=-30) create_question(question_text="Future question.", days=30) # Get client response = self.client.get(reverse('polls:index')) # Verify that question list only contains past questions self.assertQuerysetEqual( response.context['latest_question_list'], ['<Question: Past question.>'] ) # 10 Make sure question list shows multiple questions def test_index_view_with_two_past_questions(self): # Create questions create_question(question_text="Past question 1.", days=-30) create_question(question_text="Past question 2.", days=-5) # Create client response = self.client.get(reverse('polls:index')) # Verify that both questions show self.assertQuerysetEqual( response.context['latest_question_list'], ['<Question: Past question 2.>', '<Question: Past question 1.>'] ) # 11 Make sure future questions can't be accessed if the user # guess the URL in polls/views.py # 13 Add tests to make sure future posts aren't shown in detail class QuestionIndexDetailTests(TestCase): # 13 Make sure future question detail pages show 404 def test_detail_view_with_a_future_question(self): # Create question future_question = create_question(question_text='Future question.', days=5) # Open url using the future question in the url url = reverse('polls:detail', args=(future_question.id,)) # Get client response response = self.client.get(url) # Verify that it returns 404 self.assertEqual(response.status_code, 404) # 13 Verify that past questions show in detail def test_detail_view_with_a_past_question(self): # Create question past_question = create_question(question_text='Past Question.', days=-5) # Open url with past question url = reverse('polls:detail', args=(past_question.id,)) # Get response response = self.client.get(url) # Verify the question shows self.assertContains(response, past_question.question_text) # ---------- /polls/models.py ---------- from django.db import models import datetime from django.utils import timezone class Question(models.Model): question_text = models.CharField(max_length=200) pub_date = models.DateTimeField('date published') def __str__(self): return self.question_text def was_published_recently(self): # 5 return self.pub_date >= timezone.now() - datetime.timedelta(days=1) # 5 Fix the code now = timezone.now() return now - datetime.timedelta(days=1) <= self.pub_date <= now # 5 Now the test will pass # 5 Add further tests to polls/tests.py class Choice(models.Model): question = models.ForeignKey(Question, on_delete=models.CASCADE) choice_text = models.CharField(max_length=200) votes = models.IntegerField(default=0) def __str__(self): return self.choice_text # ---------- /polls/admin.py ---------- from django.contrib import admin # 9 Add choice to imports from .models import Question, Choice admin.site.register(Question) # 9 Add Choice to the Admin page admin.site.register(Choice) # 9 Create some future questions # 9 Add some tests in polls/tests.py |
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