Django基础，Day6 - 单元测试tests

在django项目app目录下，有个tests.py,我们通常可以直接在这文件中写我们的单元测试代码。

test for a model

根据前面章节的操作步骤下来，在Question Model中有一个函数 was_published_recently(),判断文章发表时间在当前一天之内。代码如

def was_published_recently(self):
      return self.pub_date >= timezone.now() - datetime.timedelta(days=1)

仔细检查，可发现上述函数有个bug。如果发表时间在未来呢，按照上面的代码是会返回true的，显然不对。

编写测试用例 polls/tests.py：

from django.test import TestCase
import datetime
from django.utils import timezone
from .models import Question

class QuestionMethodTests(TestCase):

    def test_was_published_recently_with_future_question(self):
        """
        was_published_recently() should return 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)

运行测试用例

$ python manage.py test polls

运行结果如：

Creating test database for alias 'default'...
F
======================================================================
FAIL: test_was_published_recently_with_future_question (polls.tests.QuestionMethodTests)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "E:\workspace_python\mysite\polls\tests.py", line , in test_was_published_recently_with_future_question
    self.assertIs(future_question.was_published_recently(), False)
AssertionError: True is not False

----------------------------------------------------------------------
Ran  test in .002s

FAILED (failures=)
Destroying test database for alias 'default'...

What happened is this:

• python manage.py test polls looked for tests in the polls application
• it found a subclass of the django.test.TestCase class
• it created a special database for the purpose of testing
• it looked for test methods - ones whose names begin with test
• in test_was_published_recently_with_future_question it created a Question instance whose pub_datefield is 30 days in the future
• ... and using the assertIs() method, it discovered that its was_published_recently() returns True, though we wanted it to return False

修复该bug，代码如

def was_published_recently(self):
    now = timezone.now()
    return now - datetime.timedelta(days=1) <= self.pub_date <= now

重新运行测试代码,则用例通过。

$ python manage.py test polls
Creating test database for alias 'default'...
.
----------------------------------------------------------------------
Ran  test in .001s

OK
Destroying test database for alias 'default'...

添加更多的测试用例，如

from django.test import TestCase
import datetime
from django.utils import timezone
from .models import Question

class QuestionMethodTests(TestCase):

    def test_was_published_recently_with_future_question(self):
        """
        was_published_recently() should return 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() should return False for questions whose
        pub_date is older than 1 day.
        """
        time = timezone.now() - datetime.timedelta(days=30)
        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() should return True for questions whose
        pub_date is within the last day.
        """
        time = timezone.now() - datetime.timedelta(hours=1)
        recent_question = Question(pub_date=time)
        self.assertIs(recent_question.was_published_recently(), True)

test for a view

以view.index 为例，显然现在的代码也有bug，显示了发布时间属于将来的文章，代码如

测试之前，先修复view.index 中应该不显示发布时间在将来的文章。测试代码代码如

polls/views.py:

polls/index.html:

测试用例代码

Django provides a test Client to simulate a user interacting with the code at the view level

from django.test import TestCase
import datetime
from django.urls import reverse
from django.utils import timezone
from .models import Question

class QuestionViewTests(TestCase):
    def test_index_view_with_no_questions(self):
        """
        If no questions 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_question_list'], [])

    def test_index_view_with_a_past_question(self):
        """
        Questions with a pub_date in the past should be 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_index_view_with_a_future_question(self):
        """
        Questions with a pub_date in the future should not be 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_index_view_with_future_question_and_past_question(self):
        """
        Even if both past and future questions exist, only past questions
        should be 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_index_view_with_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.>']
        )

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