5.2 Improving our view & Testing our new view

first_django_app.md

@@ -529,3 +529,139 @@ Write more tests to make sure it's comprehensive
         recent_question = Question(pub_date=time)
         self.assertIs(recent_question.was_published_recently(), True)
 ```
+
+### 5.2 Test a view
+
+Target: 如果 pub_date 设置为未来某天，这应该被解释为这个问题将在所填写的时间点才被发布，而在之前是不可见的。
+
+#### A test for a view
+
+We use TDD (i.e. test first, then develop)
+
+#### The Django test client
+
+Django provides a test **Client** (a class) to simulate a user interacting with the code at the view level.
+
+We can try it in interactive shell following the guide
+
+#### Improving our view
+
+Add following in `tests.py`
+
+```python
+def create_question(question_text, days):
+    """
+    Create a question with the given `question_text` and published the
+    given number of `days` offset to now (negative for questions published
+    in the past, positive for questions that have yet to be published).
+    """
+    time = timezone.now() + datetime.timedelta(days=days)
+    return Question.objects.create(question_text=question_text, pub_date=time)
+
+
+class QuestionIndexViewTests(TestCase):
+    def test_no_questions(self):
+        """
+        If no questions exist, an appropriate message is 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_question_list'], [])
+
+    def test_past_question(self):
+        """
+        Questions with a pub_date in the past are displayed on the
+        index page.
+        """
+        create_question(question_text="Past question.", days=-30)
+        response = self.client.get(reverse('polls:index'))
+        self.assertQuerysetEqual(
+            response.context['latest_question_list'],
+            ['<Question: Past question.>']
+        )
+
+    def test_future_question(self):
+        """
+        Questions with a pub_date in the future aren't displayed on
+        the index page.
+        """
+        create_question(question_text="Future question.", days=30)
+        response = self.client.get(reverse('polls:index'))
+        self.assertContains(response, "No polls are available.")
+        self.assertQuerysetEqual(response.context['latest_question_list'], [])
+
+    def test_future_question_and_past_question(self):
+        """
+        Even if both past and future questions exist, only past questions
+        are displayed.
+        """
+        create_question(question_text="Past question.", days=-30)
+        create_question(question_text="Future question.", days=30)
+        response = self.client.get(reverse('polls:index'))
+        self.assertQuerysetEqual(
+            response.context['latest_question_list'],
+            ['<Question: Past question.>']
+        )
+
+    def test_two_past_questions(self):
+        """
+        The questions index page may display multiple questions.
+        """
+        create_question(question_text="Past question 1.", days=-30)
+        create_question(question_text="Past question 2.", days=-5)
+        response = self.client.get(reverse('polls:index'))
+        self.assertQuerysetEqual(
+            response.context['latest_question_list'],
+            ['<Question: Past question 2.>', '<Question: Past question 1.>']
+        )
+```
+
+Testing generated
+
+```
+Creating test database for alias 'default'...
+System check identified no issues (0 silenced).
+FF......
+======================================================================
+FAIL: test_future_question (polls.tests.QuestionIndexViewTests)
+Questions with a pub_date in the future aren't displayed on
+----------------------------------------------------------------------
+Traceback (most recent call last):
+  File "/home/jason/HomeWorkstation/SynologyGiteaSpace/djangoproject/src/polls/tests.py", line 77, in test_future_question
+    self.assertContains(response, "No polls are available.")
+  File "/home/jason/miniconda3/envs/django/lib/python3.8/site-packages/django/test/testcases.py", line 470, in assertContains
+    self.assertTrue(real_count != 0, msg_prefix + "Couldn't find %s in response" % text_repr)
+AssertionError: False is not true : Couldn't find 'No polls are available.' in response
+
+======================================================================
+FAIL: test_future_question_and_past_question (polls.tests.QuestionIndexViewTests)
+Even if both past and future questions exist, only past questions
+----------------------------------------------------------------------
+Traceback (most recent call last):
+  File "/home/jason/HomeWorkstation/SynologyGiteaSpace/djangoproject/src/polls/tests.py", line 88, in test_future_question_and_past_question
+    self.assertQuerysetEqual(
+  File "/home/jason/miniconda3/envs/django/lib/python3.8/site-packages/django/test/testcases.py", line 1052, in assertQuerysetEqual
+    return self.assertEqual(list(items), values, msg=msg)
+AssertionError: Lists differ: ['<Question: Future question.>', '<Question: Past question.>'] != ['<Question: Past question.>']
+
+First differing element 0:
+'<Question: Future question.>'
+'<Question: Past question.>'
+
+First list contains 1 additional elements.
+First extra element 1:
+'<Question: Past question.>'
+
+- ['<Question: Future question.>', '<Question: Past question.>']
++ ['<Question: Past question.>']
+
+----------------------------------------------------------------------
+Ran 8 tests in 0.018s
+
+FAILED (failures=2)
+Destroying test database for alias 'default'...
+```
+
+Fix it by change `get_queryset()` method in Question. 让他它能通过将 Question 的 pub_data 属性与 timezone.now() 相比较来判断是否应该显示此 Question
+

src/polls/tests.py

@@ -2,6 +2,7 @@ import datetime
 
 from django.test import TestCase
 from django.utils import timezone
+from django.urls import reverse
 
 from .models import Question
 
@@ -33,3 +34,70 @@ class QuestionModelTests(TestCase):
         time = timezone.now() - datetime.timedelta(hours=23, minutes=59, seconds=59)
         recent_question = Question(pub_date=time)
         self.assertIs(recent_question.was_published_recently(), True)
+
+def create_question(question_text, days):
+    """
+    Create a question with the given `question_text` and published the
+    given number of `days` offset to now (negative for questions published
+    in the past, positive for questions that have yet to be published).
+    """
+    time = timezone.now() + datetime.timedelta(days=days)
+    return Question.objects.create(question_text=question_text, pub_date=time)
+
+
+class QuestionIndexViewTests(TestCase):
+    def test_no_questions(self):
+        """
+        If no questions exist, an appropriate message is 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_question_list'], [])
+
+    def test_past_question(self):
+        """
+        Questions with a pub_date in the past are displayed on the
+        index page.
+        """
+        create_question(question_text="Past question.", days=-30)
+        response = self.client.get(reverse('polls:index'))
+        self.assertQuerysetEqual(
+            response.context['latest_question_list'],
+            ['<Question: Past question.>']
+        )
+
+    def test_future_question(self):
+        """
+        Questions with a pub_date in the future aren't displayed on
+        the index page.
+        """
+        create_question(question_text="Future question.", days=30)
+        response = self.client.get(reverse('polls:index'))
+        self.assertContains(response, "No polls are available.")
+        self.assertQuerysetEqual(response.context['latest_question_list'], [])
+
+    def test_future_question_and_past_question(self):
+        """
+        Even if both past and future questions exist, only past questions
+        are displayed.
+        """
+        create_question(question_text="Past question.", days=-30)
+        create_question(question_text="Future question.", days=30)
+        response = self.client.get(reverse('polls:index'))
+        self.assertQuerysetEqual(
+            response.context['latest_question_list'],
+            ['<Question: Past question.>']
+        )
+
+    def test_two_past_questions(self):
+        """
+        The questions index page may display multiple questions.
+        """
+        create_question(question_text="Past question 1.", days=-30)
+        create_question(question_text="Past question 2.", days=-5)
+        response = self.client.get(reverse('polls:index'))
+        self.assertQuerysetEqual(
+            response.context['latest_question_list'],
+            ['<Question: Past question 2.>', '<Question: Past question 1.>']
+        )

src/polls/views.py

@@ -3,6 +3,7 @@ from django.shortcuts import render, get_object_or_404
 from django.template import loader
 from django.urls import reverse
 from django.views import generic
+from django.utils import timezone
 
 from .models import Question, Choice
 
@@ -11,8 +12,13 @@ class IndexView(generic.ListView):
     context_object_name = 'latest_question_list'
 
     def get_queryset(self):
-        """Return the last five published questions."""
+        """
-        return Question.objects.order_by('-pub_date')[:5]
+        Return the last five published questions (not including those set to be published in the future).
+        """
+        return Question.objects.filter(
+            pub_date__lte=timezone.now()
+        ).order_by('-pub_date')[:5]
+        # return Question.objects.order_by('-pub_date')[:5]
 
 class DetailView(generic.DetailView):
     model = Question