5.1 Testing the DetailView

first_django_app.md

@@ -417,3 +417,277 @@ class ResultsView(generic.DetailView):
 * 我们提供 context_object_name 属性，表示我们想使用 latest_question_list
 
 重启服务器后，就是新的投票应用（同样的html），但是内部用了generic view
+
+## Part 5 Automated Test
+
+TDD with python. Always stick to it.
+
+### 5.1 First test
+
+#### Create/Verify a bug
+
+幸运的是，我们的 polls 应用现在就有一个小 bug 需要被修复：我们的要求是如果 Question 是在一天之内发布的， Question.was_published_recently() 方法将会返回 True ，然而现在这个方法在 Question 的 pub_date 字段比当前时间还晚时也会返回 True（这是个 Bug）。
+
+确认bug:
+
+```
+>>> import datetime
+>>> from django.utils import timezone
+>>> from polls.models import Question
+>>> # create a Question instance with pub_date 30 days in the future
+>>> future_question = Question(pub_date=timezone.now() + datetime.timedelta(days=30))
+>>> # was it published recently?
+>>> future_question.was_published_recently()
+True
+```
+
+#### Create a test to verify this bug
+
+All tests (polls/tests.py) are in app directory
+
+```python
+import datetime
+
+from django.test import TestCase
+from django.utils import timezone
+
+from .models import Question
+
+class QuestionModelTests(TestCase):
+
+    def test_was_published_recently_with_future_question(self):
+        """
+        was_published_recently() returns False for questions whose pub_date is in future
+        """
+
+        time = timezone.now() + datetime.timedelta(days=30)
+        future_question = Question(pub_date=time)
+        self.assertIs(future_question.was_published_recently(), False)
+```
+
+Result
+
+```
+python manage.py test polls
+Creating test database for alias 'default'...
+System check identified no issues (0 silenced).
+F
+======================================================================
+FAIL: test_was_published_recently_with_future_question (polls.tests.QuestionModelTests)
+was_published_recently() returns False for questions whose pub_date is in future
+----------------------------------------------------------------------
+Traceback (most recent call last):
+  File "/home/jason/HomeWorkstation/SynologyGiteaSpace/djangoproject/src/polls/tests.py", line 17, in test_was_published_recently_with_future_question
+    self.assertIs(future_question.was_published_recently(), False)
+AssertionError: True is not False
+
+----------------------------------------------------------------------
+Ran 1 test in 0.001s
+
+FAILED (failures=1)
+Destroying test database for alias 'default'...
+```
+
+解释上述msg:
+* python manage.py test polls 将会寻找 polls 应用里的测试代码
+* 它找到了 django.test.TestCase 的一个子类
+* 它创建一个特殊的数据库供测试使用
+* 它在类中寻找测试方法——以 test 开头的方法。
+* 在 test_was_published_recently_with_future_question 方法中，它创建了一个 pub_date 值为 30 天后的 Question 实例。
+* 接着使用 assertls() 方法，发现 was_published_recently() 返回了 True，而我们期望它返回 False。
+
+#### Fix the bug
+
+Fix bug in `polls/models.py`
+
+```python
+    def was_published_recently(self):
+        now = timezone.now()
+        return now - datetime.timedelta(days=1) <= self.pub_date <= now
+```
+
+#### Comprehensive Tests
+
+Write more tests to make sure it's comprehensive
+
+```python
+    def test_was_published_recently_with_old_question(self):
+        """
+        was_published_recently() returns False for questions whose pub_date is older than 1 day.
+        """
+
+        time = timezone.now() - datetime.timedelta(days=1, seconds=1)
+        old_quesion = Question(pub_date=time)
+        self.assertIs(old_quesion.was_published_recently(), False)
+
+    def test_was_published_recently_with_recent_question(self):
+        """
+        was_published_recently() returns True for questions whose pub_date is within the last day.
+        """
+
+        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)
+```
+
+### 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
+
+#### Test and Improve 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
+
+#### Testing the DetailView
+
+Target: hide future questions even if user type correct URL
+
+Add test cases first
+
+```python
+class QuestionDetailViewTests(TestCase):
+    def test_future_question(self):
+        """
+        The detail view of a question with a pub_date in the future returns a 404 not found.
+        """
+        future_question = create_question(question_text="Future question.", days=5)
+        url = reverse('poll:detail', args=(future_question.id, ))
+        response = self.client.get(url)
+        self.assertEqual(response.status_code, 404)
+
+    def test_past_questioin(self):
+        """
+        The detail view of a question with a pub_date in the past displays the question's text.
+        """
+        past_question = create_question(question_text='Past Question.', days=-5)
+        url = reverse('polls:detail', args=(past_question.id,))
+        response = self.client.get(url)
+        self.assertContains(response, past_question.question_text)
+```

src/polls/models.py

@@ -1,7 +1,7 @@
 import datetime
 
 from django.db import models
-from django.utils import timezone as djtz
+from django.utils import timezone
 
 class Question(models.Model):
     # question_text & pub_date are instances of field
@@ -9,7 +9,8 @@ class Question(models.Model):
     pub_date = models.DateTimeField('date published')
 
     def was_published_recently(self):
-        return self.pub_date >= djtz.now() - datetime.timedelta(days=1)
+        now = timezone.now()
+        return now - datetime.timedelta(days=1) <= self.pub_date <= now
 
     def __str__(self) -> str:
         return self.question_text

src/polls/tests.py

@@ -1,3 +1,124 @@
-from django.test import TestCase
+import datetime
+from django.conf.urls import url
+from django.http import response
 
-# Create your tests here.
+from django.test import TestCase
+from django.utils import timezone
+from django.urls import reverse
+
+from .models import Question
+
+class QuestionModelTests(TestCase):
+
+    def test_was_published_recently_with_future_question(self):
+        """
+        was_published_recently() returns False for questions whose pub_date is in future
+        """
+
+        time = timezone.now() + datetime.timedelta(days=30)
+        future_question = Question(pub_date=time)
+        self.assertIs(future_question.was_published_recently(), False)
+
+    def test_was_published_recently_with_old_question(self):
+        """
+        was_published_recently() returns False for questions whose pub_date is older than 1 day.
+        """
+
+        time = timezone.now() - datetime.timedelta(days=1, seconds=1)
+        old_quesion = Question(pub_date=time)
+        self.assertIs(old_quesion.was_published_recently(), False)
+
+    def test_was_published_recently_with_recent_question(self):
+        """
+        was_published_recently() returns True for questions whose pub_date is within the last day.
+        """
+
+        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.>']
+        )
+
+class QuestionDetailViewTests(TestCase):
+    def test_future_question(self):
+        """
+        The detail view of a question with a pub_date in the future returns a 404 not found.
+        """
+        future_question = create_question(question_text="Future question.", days=5)
+        url = reverse('polls:detail', args=(future_question.id, ))
+        response = self.client.get(url)
+        self.assertEqual(response.status_code, 404)
+
+    def test_past_questioin(self):
+        """
+        The detail view of a question with a pub_date in the past displays the question's text.
+        """
+        past_question = create_question(question_text='Past Question.', days=-5)
+        url = reverse('polls:detail', args=(past_question.id,))
+        response = self.client.get(url)
+        self.assertContains(response, past_question.question_text)

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
 
@@ -11,13 +12,24 @@ 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
     template_name = 'polls/detail.html'
 
+    def get_queryset(self):
+        """
+        Excludes any questions that aren't published yet
+        """
+        return Question.objects.filter(pub_date__lte=timezone.now())
+
 class ResultsView(generic.DetailView):
     model = Question
     template_name = 'polls/results.html'