# TTD(测试驱动):开发环境第一个测试 ## TDD * 测试驱动开发：首先编写测试 * 每次只前进一步 ## 开始项目 * 创建项目目录，新建`functional_tests.py` ``` from selenium import webdriver browser = webdriver.Firefox() browser.get('http://localhost:8000') assert 'Django' in browser.title ``` 尝试执行 ``` python3 functional_tests.py ``` 显示错误 ``` FileNotFoundError: [Errno 2] No such file or directory: 'geckodriver' ``` 看来缺少了FireFox的驱动核心`gecko`，参考 [How to install firefoxdriver webdriver for python3 selenium on ubuntu 16.04?](http://stackoverflow.com/questions/39179320/how-to-install-firefoxdriver-webdriver-for-python3-selenium-on-ubuntu-16-04): * 高于FireFox 47的Firefox使用新型驱动，有两种解决方法： * 下载和降级到Firefox 46 * 下载最新的Marionette驱动并修改代码适应新环境 参考 [Installing Selenium and ChromeDriver on Ubuntu](https://christopher.su/2015/selenium-chromedriver-ubuntu/#selenium-version) 以及 [Marionette > WebDriver](https://developer.mozilla.org/en-US/docs/Mozilla/QA/Marionette/WebDriver) * 下载[最新的geckdriver](https://github.com/mozilla/geckodriver/releases) ``` cd ~/bin tar xfz geckodriver-v0.14.0-macos.tar.gz ``` * 然后配置 ``` export PATH=$PATH:/path/to/geckodriver ``` 此时再次执行 `python3 functional_tests.py` 就可以看到打开了本地firefox浏览器访问测试页面 ## 运行Django ``` django-admin.py startproject superlists ``` 上述`django-admin.py`命令会创建一个`superlists`文件夹并创建一些结构文件。现在我们开始运行Django: ``` cd superlists python3 manage.py runserver ``` 这里有一个提示 ``` You have 13 unapplied migration(s). Your project may not work properly until you apply the migrations for app(s): admin, auth, contenttypes, sessions. Run 'python manage.py migrate' to apply them. ``` 尝试 `python manage.py migrate` 则提示 ``` Traceback (most recent call last): File "manage.py", line 17, in "Couldn't import Django. Are you sure it's installed and " ImportError: Couldn't import Django. Are you sure it's installed and available on your PYTHONPATH environment variable? Did you forget to activate a virtual environment? ``` 这个`PYTHONPATH`环境问题参考 [Django installed, but can't import django in python](https://askubuntu.com/questions/250442/django-installed-but-cant-import-django-in-python) 执行命令检查路径 ``` $ python3 >>> import sys >>> sys.path ['', '/Library/Frameworks/Python.framework/Versions/3.6/lib/python36.zip', '/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6', '/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/lib-dynload', '/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages'] ``` 需要执行类似 ``` $ PYTHONPATH=/path/to/django/parent/dir python >>> import django # should work now ``` 实际操作可以使用 ``` PTTHONPATH=/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/django python3 ``` > 建议使用 `virtualenv` 来构建环境。 **不过上述错误实际上是我忘记python2没有安装django，需要使用`python3`** 再次运行 `python3 functional_tests.py` 就可以看到Django正常工作的提示界面： ![Django work](https://github.com/huataihuang/cloud-atlas-draft/tree/6f3204fffc11cf006abd394631e2598d98b415c3/ime/develop/python/django/django_work.png) ## 创建Git仓库 在阶段性完成工作后，需要将代码提交到版本控制系统。 将开发的第一个python代码移动到 `superlists` 目录下，然后开始初始化软件仓库 ``` $ ls functional_tests.py superlists $ mv functional_tests.py superlists/ $ cd superlists/ $ ls db.sqlite3 manage.py functional_tests.py superlists $ git init . Initialized empty Git repository in /Users/huatai/Dropbox/works/tdd-python/superlists/.git/ ``` 目录中有一个`db.sqlite3`是数据库文件，这个文件不用纳入版本控制，所以将这个文件加入到`.gitignore`，告诉git将其忽略： ``` $ echo "db.sqlite3" >> .gitignore ``` 接下来添加当前文件夹`.`中其他内容： ``` $ git add . $ git status On branch master Initial commit Changes to be committed: (use "git rm --cached ..." to unstage) new file: .gitignore new file: functional_tests.py new file: manage.py new file: superlists/__init__.py new file: superlists/__pycache__/__init__.cpython-36.pyc new file: superlists/__pycache__/settings.cpython-36.pyc new file: superlists/__pycache__/urls.cpython-36.pyc new file: superlists/__pycache__/wsgi.cpython-36.pyc new file: superlists/settings.py new file: superlists/urls.py new file: superlists/wsgi.py ``` 此时发现我们错误添加了很多`.pyc`文件，这些文件没有必要提交。所以将这些文件从git中删除，并添加到`.gitignore`中： ``` $ git rm -r --cached superlists/__pycache__ rm 'superlists/__pycache__/__init__.cpython-36.pyc' rm 'superlists/__pycache__/settings.cpython-36.pyc' rm 'superlists/__pycache__/urls.cpython-36.pyc' rm 'superlists/__pycache__/wsgi.cpython-36.pyc' $ echo "__pycache__" >> .gitignore $ echo "*.pyc" >> .gitignore ``` 现在再次使用`git status`检查状态，没有问题我们就可以提交软件仓库了 ``` git commit ``` ## 第一个测试 ``` #!/usr/bin/env python3 from selenium import webdriver import unittest class NewVisistorTest(unittest.TestCase): def setUp(self): self.browser = webdriver.Firefox() def tearDown(self): self.browser.quit() def test_can_start_a_list_and_retrieve_it_later(self): self.browser.get('http://localhost:8000') self.assertIn('To-Do', self.browser.title) self.fail('finish the test!') if __name__ == '__main__': unittest.main(warnings='ignore') ``` * 设置程序运行使用系统中`python3` ``` #!/usr/bin/env python3 ``` * 测试代码`test_can_start_a_list_and_retrieve_it_later`，所有以`test_`开头的方法都是测试方法，由测试主程序运行。类中可以定义多个测试方法。 * `setUp`和`tearDown`是特殊方法，分别在测试方法之前和之后运行，这里使用两个方法打开和关闭浏览器。这两个方法类似`try/except`依据，如果测试出错，也会运行`tearDown`方法，这样测试结束，Firefox窗口就会关闭。 > 如果`setUp`方法抛出异常，则`tearDown`方法不会运行 * `unittest`提供了很多用于编写测试断言的辅助函数，如`assertEqual`、`assertTrue`和`assertFalse`等，详细参考 * `if __name__ == '__main__` 是用于检查python程序是否在命令行运行，而不是其他脚本中导入。调用`unittest.main()`启动`unittest`测试运行程序会自动在文件中查找测试类和方法，然后运行。 * `warnings='ignore'`会禁止抛出`ResourceWarning`异常。 执行以上测试，会看到启动Firefox，并输出测试包报告，显示了测试失败的内容 ``` $ ./functional_tests.py F ====================================================================== FAIL: test_can_start_a_list_and_retrieve_it_later (__main__.NewVisistorTest) ---------------------------------------------------------------------- Traceback (most recent call last): File "./functional_tests.py", line 15, in test_can_start_a_list_and_retrieve_it_later self.assertIn('To-Do', self.browser.title) AssertionError: 'To-Do' not found in 'Welcome to Django' ---------------------------------------------------------------------- Ran 1 test in 3.165s FAILED (failures=1) ``` 很好，我们现在知道访问的浏览器标题窗口没有`To-Do`关键字 * Selenium测试中还经常使用等待页面加载的指令`implicitly_wait`，以便Selenium能等待页面完全加载。 ``` def setUp(self): self.browser = webdriver.Firefox() self.browser.implicitly_wait(3) ``` > `implicitly_wait`不适合所有情况，复杂测试需要显式等待 ## 参考 * [Browser Automation Using Selenium](https://www.geeksforgeeks.org/browser-automation-using-selenium/) --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. 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