docs: Add 05-test.md

Author: devpla

docs/05-test.md

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+# 05. Test
+
+> **테스트를 만들어야하는 이유**
+> - (자동화된) 테스트를 통해 시간을 절약할 수 있습니다.
+> - 테스트는 문제를 그저 식별하는 것이 아니라 예방합니다.
+> - 테스트가 코드를 더 매력적으로 만듭니다.
+> - 테스트는 팀이 함께 일하는 것을 돕습니다.
+
+## 버그
+### 버그 식별하기
+```bash
+$ python manage.py shell
+Python 3.9.6 (tags/v3.9.6:db3ff76, Jun 28 2021, 15:26:21) [MSC v.1929 64 bit (AMD64)] on win32
+Type "help", "copyright", "credits" or "license" for more information.
+(InteractiveConsole)
+```
+```python
+>>> 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()
+True
+```
+- 미래는 최근이 아닌데 최근이라고 나온다.
+
+### 버그를 노출하는 테스트 만들기
+- AssertionError
+- `polls/test.py`
+```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 the future.
+        """
+        time = timezone.now() + datetime.timedelta(days=30)
+        future_question = Question(pub_date=time)
+        self.assertIs(future_question.was_published_recently(), False)
+```
+```bash
+$ 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
+----------------------------------------------------------------------
+Traceback (most recent call last):
+  File "C:\Users\User\django-tutorial\mysite\polls\tests.py", line 18, 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'...
+```
+
+### 버그 수정
+- `polls/models.py`
+```python
+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):
+    #     return self.pub_date >= timezone.now() - datetime.timedelta(days=1)
+    def was_published_recently(self):
+        now = timezone.now()
+        return now - datetime.timedelta(days=1) <= self.pub_date <= now
+```
+
+- 테스트 다시 실행
+```bash
+$ python manage.py test polls
+Creating test database for alias 'default'...
+System check identified no issues (0 silenced).
+.
+----------------------------------------------------------------------
+Ran 1 test in 0.001s
+
+OK
+Destroying test database for alias 'default'...
+```
+
+### 테스트 메서드 추가
+```python
+class QuestionModelTests(TestCase):
+
+    def test_was_published_recently_with_future_question(self):
+        """
+        was_published_recently() returns False for questions whose pub_date
+        is in the 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_question = Question(pub_date=time)
+        self.assertIs(old_question.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)
+```
+
+## 뷰 테스트
+
+### 테스트 클라이언트 사용하기
+```bash
+$ python manage.py shell
+Python 3.9.6 (tags/v3.9.6:db3ff76, Jun 28 2021, 15:26:21) [MSC v.1929 64 bit (AMD64)] on win32
+Type "help", "copyright", "credits" or "license" for more information.
+(InteractiveConsole)
+```
+```python
+>>> from django.test.utils import setup_test_environment
+>>> setup_test_environment()
+>>> from django.test import Client
+>>> client = Client()
+>>> response = client.get('/')
+Not Found: /
+>>> response.status_code
+404
+>>> from django.urls import reverse
+>>> response = client.get(reverse('polls:index'))
+>>> response.status_code
+200
+>>> response.content
+b'\n  <ul>\n    \n      <li><a href="/polls/1/">What&#x27;s up?</a></li>\n    \n  </ul>\n'
+>>> response.context['latest_question_list']
+<QuerySet [<Question: What's up?>]>
+```
+
+### 뷰 개선
+- 아직 개시되지 않은 설문조사 표시 수정하기
+- `polls/views.py`
+```python
+from django.utils import timezone
+
+class IndexView(generic.ListView):
+    template_name = 'polls/index.html'
+    context_object_name = 'latest_question_list'
+
+    # def get_queryset(self):
+    #     """Return the last five published questions."""
+    #     return Question.objects.order_by('-pub_date')[:5]
+    def get_queryset(self):
+        """
+        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]
+```
+
+### 새로운 뷰 테스트
+- `polls/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.
+        """
+        question = create_question(question_text="Past question.", days=-30)
+        response = self.client.get(reverse('polls:index'))
+        self.assertQuerysetEqual(
+            response.context['latest_question_list'],
+            [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.
+        """
+        question = 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],
+        )
+
+    def test_two_past_questions(self):
+        """
+        The questions index page may display multiple questions.
+        """
+        question1 = create_question(question_text="Past question 1.", days=-30)
+        question2 = create_question(question_text="Past question 2.", days=-5)
+        response = self.client.get(reverse('polls:index'))
+        self.assertQuerysetEqual(
+            response.context['latest_question_list'],
+            [question2, question1],
+        )
+```
+
+```bash
+$ python manage.py test polls
+Creating test database for alias 'default'...
+System check identified no issues (0 silenced).
+........
+----------------------------------------------------------------------
+Ran 8 tests in 0.024s
+
+OK
+Destroying test database for alias 'default'...
+```
+
+### DetailView 테스트
+- `polls/views.py`
+```python
+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())
+```
+
+- `polls/tests.py`
+```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('polls:detail', args=(future_question.id,))
+        response = self.client.get(url)
+        self.assertEqual(response.status_code, 404)
+
+    def test_past_question(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)
+```
+```bash
+$ python manage.py test polls
+Creating test database for alias 'default'...
+System check identified no issues (0 silenced).
+..........
+----------------------------------------------------------------------
+Ran 10 tests in 0.045s
+
+OK
+Destroying test database for alias 'default'...
+```
+
+- 그 외 : 장고 테스트 [공식문서](https://docs.djangoproject.com/ko/3.2/topics/testing/)