使用Unittest测试简单主页

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如何进行单元测试

创建Django应用并编写第一个测试用例

执行命令 python manage.py startapp lists 创建一个叫lists的应用。

在lists/tests.py 里输入第一个测试用例：

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from django.test import TestCase

class SmokeTest(TestCase):

    def test_bad_maths(self):
        self.assertEqual(1 + 1, 3)

在命令行里执行python manage.py test，可能的结果如下：

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$ python manage.py test
Creating test database for alias 'default'...
F
======================================================================
FAIL: test_bad_maths (lists.tests.SmokeTest)
 ---------------------------------------------------------------------
Traceback (most recent call last):
  File "...python-tdd-book/lists/tests.py", line 6, in test_bad_maths
    self.assertEqual(1 + 1, 3)
AssertionError: 2 != 3

 ---------------------------------------------------------------------
Ran 1 test in 0.001s

FAILED (failures=1)
System check identified no issues (0 silenced).
Destroying test database for alias 'default'...

创建测试用例

接下来，考虑书写正式的测试用例。

测试视图函数和路由相匹配

修改lists/tests.py内容如下，以测试跟路由/是否和函数home_page对应（虽然该函数现在还没写）

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from django.urls import resolve
from django.test import TestCase
from lists.views import home_page  

class HomePageTest(TestCase):

    def test_root_url_resolves_to_home_page_view(self):
        found = resolve('/')  
        self.assertEqual(found.func, home_page)

此时执行单元测试一定会失败，报错home_page未定义。

在lists/views.py里添加如下内容

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from django.shortcuts import render

# Create your views here.
home_page = None

再次运行，报错为路由/未找到。

在superlists/urls.py添加如下代码：

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from django.contrib import admin
from django.conf.urls import url
from lists import views

urlpatterns = [
    url(r'^$', views.home_page, name='home'),
    url(r'^admin/', admin.site.urls),
]

此时单元测试结果如下，视图函数必须是callable。

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[...]
TypeError: view must be a callable or a list/tuple in the case of include().

修改lists/views.py内容如下

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from django.shortcuts import render

# Create your views here.
def home_page():
    pass

运行单元测试，可以看到已经能通过了：

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$ python manage.py test
Creating test database for alias 'default'...
.
 ---------------------------------------------------------------------
Ran 1 test in 0.003s

OK
System check identified no issues (0 silenced).
Destroying test database for alias 'default'...

测试路由的返回值

可以通过：

  • 测试返回值是否以<html>标记开头
  • 测试返回值是否以</html>标记结尾
  • 测试返回值的<title>标记内容

在lists/tests.py的HomePageTest类里添加第二个单元测试：

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from django.urls import resolve
from django.test import TestCase
from django.http import HttpRequest

from lists.views import home_page


class HomePageTest(TestCase):

    def test_root_url_resolves_to_home_page_view(self):
        found = resolve('/')
        self.assertEqual(found.func, home_page)


    def test_home_page_returns_correct_html(self):
        request = HttpRequest()  
        response = home_page(request)  
        html = response.content.decode('utf8')  
        self.assertTrue(html.startswith('<html>'))  
        self.assertIn('<title>To-Do lists</title>', html)  
        self.assertTrue(html.endswith('</html>'))

执行单元测试报错：TypeError: home_page() takes 0 positional arguments but 1 was given

将lists/views.py的home_page函数修改如下：

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def home_page(request):
    return HttpResponse()

再次测试，报错：

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self.assertTrue(html.startswith('<html>'))
AssertionError: False is not true

修改lists/views.py的home_page函数：

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def home_page(request):
    return HttpResponse('<html>')

再次测试，报错：

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AssertionError: '<title>To-Do lists</title>' not found in '<html>'

修改lists/views.py的home_page函数：

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def home_page(request):
    return HttpResponse('<html><title>To-Do lists</title>')

再次测试，报错：

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self.assertTrue(html.endswith('</html>'))
AssertionError: False is not true

修改lists/views.py的home_page函数：

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def home_page(request):
    return HttpResponse('<html><title>To-Do lists</title></html>')

再次测试，就OK了：

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$ python manage.py test
Creating test database for alias 'default'...
..
 ---------------------------------------------------------------------
Ran 2 tests in 0.001s

OK
System check identified no issues (0 silenced).
Destroying test database for alias 'default'...

快速命令介绍

启动Django服务

Rpython manage.py runserver

进行功能测试

python functional_tests.py

Django运行单元测试

python manage.py test

单元测试流程（TDD）

  1. 运行单元测试
  2. 修改/编写代码
  3. 回到第一步

参考资料

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