django 學習筆記（五）

時間 2019-11-18

標籤 django 學習筆記欄目 Python 简体版

原文原文鏈接

5、Writing your first Django app, part 5

自動測試的好處

節省開發時間
避免錯誤
讓別人可以接受你的代碼，不然沒法確認質量
幫助小組協同開發

第一個測試的例子

在前面的 polls 中有個小 bug ： Poll.was_published_recently() 在Poll的發佈時間在將來的時候也返回 Truepython

經過 admin頁面能夠很容易的驗證，經過 Shell 也可以檢測出這個bug。 python manage.py shellweb

>>> import datetime
>>> from django.utils import timezone
>>> from polls.models import Poll
>>> # create a Poll instance with pub_date 30 days in the future
>>> future_poll = Poll(pub_date=timezone.now() + datetime.timedelta(days=30))
>>> # was it published recently?
>>> future_poll.was_published_recently()
True

1.寫一個測試來暴露出這個bug

一般項目在創建的時候會自動創建一個模擬的tests.py文件，所有刪除後改爲這樣。shell

import datetime

from django.utils import timezone
from django.test import TestCase

from polls.models import Poll

class PollMethodTests(TestCase):

    def test_was_published_recently_with_future_poll(self):
        """
        was_published_recently() should return False for polls whose
        pub_date is in the future
        """
        future_poll = Poll(pub_date=timezone.now() + datetime.timedelta(days=30))
        self.assertEqual(future_poll.was_published_recently(), False)

創建一個 django.test.TestCase 的子類 PollMethodTests , 在其中創建了一個測試方法 test_was_published_recently_with_future_poll() ，使用 assertEqual() 來驗證。數據庫

2.運行測試

python manage.py test polls

測試的執行流程django

在polls內尋找tests.py
尋找django.test.TestCase的子類
創建用於測試的數據庫
尋找以 test開頭的方法
創建實例
使用 assertEqual() 檢測結果

3.修復 bug

polls/models.py瀏覽器

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

再次運行測試，經過app

更復雜一點的測試

1天以內返回 True工具

超過1天返回 False測試

def test_was_published_recently_with_old_poll(self):
     """
     was_published_recently() should return False for polls whose pub_date
     is older than 1 day
     """
     old_poll = Poll(pub_date=timezone.now() - datetime.timedelta(days=30))
     self.assertEqual(old_poll.was_published_recently(), False)

 def test_was_published_recently_with_recent_poll(self):
     """
     was_published_recently() should return True for polls whose pub_date
     is within the last day
     """
     recent_poll = Poll(pub_date=timezone.now() - datetime.timedelta(hours=1))
     self.assertEqual(recent_poll.was_published_recently(), True)

測試一個視圖

經過工具來模擬web的行爲url

1.測試工具 client

創建測試環境

>>> from django.test.utils import setup_test_environment
 >>> setup_test_environment()

導入測試類

>>> from django.test.client import Client
 >>> client = Client()

系列測試

訪問 / 返回404

>>> response = client.get('/')
     >>> response.status_code

使用reverse方法訪問視圖

>>> from django.core.urlresolvers import reverse
     >>> response = client.get(reverse('polls:index'))
     >>> response.status_code
     >>> response.content

訪問 /polls/

>>> from polls.models import Poll
     創建一個新Poll
         >>> from django.utils import timezone
         >>> p = Poll(question="Who is your favorite Beatle?", pub_date=timezone.now())
         >>> p.save()
     >>> response = client.get('/polls/')
     >>> response.content
     >>> response.context['latest_poll_list']

2.改進視圖

不顯示將來發表的Poll，修改 view.py 中的get_queryset() 方法.

from django.utils import timezone
...
def get_queryset(self):
    """
    Return the last five published polls (not including those set to be
    published in the future).
    """
    return Poll.objects.filter(
        pub_date__lte=timezone.now()
    ).order_by('-pub_date')[:5]

經過使用 __lte的方式來篩選記錄

3.測試改進後的新視圖

可使用瀏覽器測試，也能夠經過增長 tests.py的方式測試。

from django.core.urlresolvers import reverse

def create_poll(question, days):
    """
    Creates a poll with the given `question` published the given number of
    `days` offset to now (negative for polls published in the past,
    positive for polls that have yet to be published).
    """
    return Poll.objects.create(question=question,
        pub_date=timezone.now() + datetime.timedelta(days=days))

class PollViewTests(TestCase):
    def test_index_view_with_no_polls(self):
        """
        If no polls 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_poll_list'], [])

    def test_index_view_with_a_past_poll(self):
        """
        Polls with a pub_date in the past should be displayed on the index page.
        """
        create_poll(question="Past poll.", days=-30)
        response = self.client.get(reverse('polls:index'))
        self.assertQuerysetEqual(
            response.context['latest_poll_list'],
            ['<Poll: Past poll.>']
        )

    def test_index_view_with_a_future_poll(self):
        """
        Polls with a pub_date in the future should not be displayed on the
        index page.
        """
        create_poll(question="Future poll.", days=30)
        response = self.client.get(reverse('polls:index'))
        self.assertContains(response, "No polls are available.", status_code=200)
        self.assertQuerysetEqual(response.context['latest_poll_list'], [])

    def test_index_view_with_future_poll_and_past_poll(self):
        """
        Even if both past and future polls exist, only past polls should be
        displayed.
        """
        create_poll(question="Past poll.", days=-30)
        create_poll(question="Future poll.", days=30)
        response = self.client.get(reverse('polls:index'))
        self.assertQuerysetEqual(
            response.context['latest_poll_list'],
            ['<Poll: Past poll.>']
        )

    def test_index_view_with_two_past_polls(self):
        """
        The polls index page may display multiple polls.
        """
        create_poll(question="Past poll 1.", days=-30)
        create_poll(question="Past poll 2.", days=-5)
        response = self.client.get(reverse('polls:index'))
        self.assertQuerysetEqual(
            response.context['latest_poll_list'],
             ['<Poll: Past poll 2.>', '<Poll: Past poll 1.>']
        )

create_poll 用於構造數據
空Poll狀況
```
test_index_view_with_no_polls
```
正常顯示過去的Poll
```
test_index_view_with_a_past_poll
```
將來的不顯示
```
test_index_view_with_a_future_poll
```

過去將來同時存在，只顯示過去

test_index_view_with_future_poll_and_past_poll

顯示多個polls
```
test_index_view_with_two_past_polls
```

4.測試 DetailView

防止猜想來直接訪問將來的poll

修改 DetailView方法

class DetailView(generic.DetailView):
    ...
    def get_queryset(self):
        """
        Excludes any polls that aren't published yet.
        """
        return Poll.objects.filter(pub_date__lte=timezone.now())
        Poll.objects.filter(pub_date__lte=timezone.now())

增長測試

訪問將來的poll test_detail_view_with_a_future_poll

訪問過去的poll test_detail_view_with_a_past_poll

class PollIndexDetailTests(TestCase):
     def test_detail_view_with_a_future_poll(self):
         """
         The detail view of a poll with a pub_date in the future should
         return a 404 not found.
         """
         future_poll = create_poll(question='Future poll.', days=5)
         response = self.client.get(reverse('polls:detail', args=(future_poll.id,)))
         self.assertEqual(response.status_code, 404)

     def test_detail_view_with_a_past_poll(self):
         """
         The detail view of a poll with a pub_date in the past should display
         the poll's question.
         """
         past_poll = create_poll(question='Past Poll.', days=-5)
         response = self.client.get(reverse('polls:detail', args=(past_poll.id,)))
         self.assertContains(response, past_poll.question, status_code=200)

若是設置 handler404, 狀態返回始終是 200, 測試將來的始終報錯