frist Django app — 5、Test

Test——很重要可是没有被重视起来的一个环节，至少是我本身，其实本身以前在作java web的时候就去尝试过怎么作REST接口的测试，一直没有找到一种合适方式，并且由于时间紧没有进一步深究，可是形成的后果每次作了修改以后都测试不充分，引发新的问题，因此此次对于python正好看看Django的单元测试。

用的是单独的数据库，数据库是干净的（暂未有数据库，test全部操做都是从零开始），不会对正式的数据库形成影响

Test Model

到如今咱们主要的业务逻辑代码在model和view里面，因此咱们的测试也主要是针对model和view。在Django中咱们的测试代码写在tests.py里面，这里咱们先在models.py的Question类里面添加一个was_published_recently方法：

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

接下来针对这个方法写单元测试

class QuestionMethodTest(TestCase):
    def test_was_pblished_recently_with_future_question(self):
        time = timezone.now() + datetime.timedelta(days=30)
        future_question = Question(publ_date=time)
        self.assertEqual(future_question.was_published_recently(), False)
    def test_was_pblished_recently_with_old_question(self):
        time = timezone.now() - datetime.timedelta(days=30)
        future_question = Question(publ_date=time)
        self.assertEqual(future_question.was_published_recently(), False)
    def test_was_pblished_recently_with_recently_question(self):
        time = timezone.now() - datetime.timedelta(hours=1)
        future_question = Question(publ_date=time)
        self.assertEqual(future_question.was_published_recently(), True)

这里先写了三个测试用例，分别测试

• 时间大于当前时间的是否会被查到
• 时间小于当前时间某些天的question是否会被查询到
• 时间小于当前时间一天内（咱们以前的“最近”的规则设置的就是一天）是否会被查询到

咱们再看看Django为咱们的单元测试提供了怎样的环境。

• 全部的测试继承自django.test.TestCase，TestCase提供了不少测试方法，好比：assertEqual，assertContains等
• django会查找全部以test开头的方法（又一个约定大于配置）
• 使用python manage.py test polls来运行咱们的测试，能够只对某一个app运行测试
• 每次测试进行的时候，django会建立新的数据库，测试完成以后会删除数据库，这样保证每次测试不会有污染数据

咱们在mysite目录里面运行测试

python manage.py test polls

能够看到输出

Creating test database for alias 'default'...
F..
======================================================================
FAIL: test_was_pblished_recently_with_future_question (polls.tests.QuestionMethodTest)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/root/django/mysite/polls/tests.py", line 17, in test_was_pblished_recently_with_future_question
    self.assertEqual(future_question.was_published_recently(), False)
AssertionError: True != False

----------------------------------------------------------------------
Ran 3 tests in 0.001s

FAILED (failures=1)
Destroying test database for alias 'default'...

 

能够看到总共三个测试，失败1个，查看失败信息发现返回的是true，和咱们预期的不符，说明咱们的was_published_recently函数的逻辑不正确，全部时间大于当前时间的应该不被查询出来，咱们修正以下

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

再次运行就会发现三个均成功，结果是OK

Creating test database for alias 'default'...
...
----------------------------------------------------------------------
Ran 3 tests in 0.001s

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

Test View

view层会调用model层的代码实现业务逻辑，咱们经过上面model的测试保证了model层的正确性，接下来能够借用django提供的环境测试咱们的业务逻辑是否正确，编辑tests.py

from django.test import TestCase
import datetime
from django.utils import timezone
from polls.models import Question
from django.core.urlresolvers import reverse

# Create your tests here.

def create_question(question_text, days):
    time = timezone.now() + datetime.timedelta(days=days)
    return Question.objects.create(question_text=question_text, publ_date=time)

class QuestionMethodTest(TestCase):
    def test_was_pblished_recently_with_future_question(self):
        time = timezone.now() + datetime.timedelta(days=30)
        future_question = Question(publ_date=time)
        self.assertEqual(future_question.was_published_recently(), False)
    def test_was_pblished_recently_with_old_question(self):
        time = timezone.now() - datetime.timedelta(days=30)
        future_question = Question(publ_date=time)
        self.assertEqual(future_question.was_published_recently(), False)
    def test_was_pblished_recently_with_recently_question(self):
        time = timezone.now() - datetime.timedelta(hours=1)
        future_question = Question(publ_date=time)
        self.assertEqual(future_question.was_published_recently(), True)

class QuestionViewTest(TestCase):
    def test_index_view_with_no_questions(self):
        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):
        create_question('Past question.', -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):
        create_question('Future question.', 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):
        create_question('Past question.', -30)
        create_question('Future question.', 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_question(self):
        create_question('Past question 1.', -30)
        create_question('Past question 2.', -5)
        response = self.client.get(reverse('polls:index'))
        self.assertQuerysetEqual(response.context['latest_question_list'], ['<Question: Past question 2.>', '<Question: Past question 1.>'])

View Code

django为咱们的view层测试提供了更多的帮助

• TestCase提供的包含一个client，表示一个客户端
• 能够经过client调用get，post方法获取服务器的返回值response
• 获取response的HttpCode，返回的context参数

关于测试

• more is better，test will look after themselves。测试用例越多，测试越全面，若是代码修改了，测试用例执行就会失败，就能够提醒咱们去修改相应的测试
• 一个单独的model或者view应该使用一个单独的test类
• 每一种测试状况写单独的测试方法
• 测试方法尽可能描述它的功能（见文知意）

 

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完整代码

http://pan.baidu.com/s/1geJ7DYj