Selenium Webdriver Desired Capabilities

我们每一个的selenium测试都应该在指定的环境下运行，这个环境可以是web浏览器、移动设备、移动模拟器等等。
那怎么来指定我们的selenium测试脚本运行环境呢？
本次分享主要解决这个问题！！！
在python版本的webdrive中，DesiredCapabilities类为我们提供了解决方案，通过这个类，我们能够配置webdriver在指定的环境执行我们的测试脚本。
在python版本的webdrive中，DesiredCapabilities类为我们提供了解决方案，通过这个类，我们能够配置webdriver在指定的环境执行我们的测试脚本。
我们先看一张实际测试过程中会应用到的结构图，基于selenium grid进行分布式测试：

在上图中，我们可以使用windows下ie、firefox或linux下ie、firefox进行测试，甚至可以设置使用andriod或ios设备下浏览器进行测试。
那怎么来进行设置呢？
我们先看一下DesiredCapabilities的源码

源码分析
DesiredCapabilities类代码在C:\Python27\Lib\site-packages\selenium\webdriver\common\desired_capabilities.py。
注：笔者的python安装在C盘下。

class DesiredCapabilities(object):    """    Set of default supported desired capabilities.    Use this as a starting point for creating a desired capabilities object for    requesting remote webdrivers for connecting to selenium server or selenium grid.    Usage Example::        from selenium import webdriver        selenium_grid_url = "http://198.0.0.1:4444/wd/hub"        # Create a desired capabilities object as a starting point.        capabilities = DesiredCapabilities.FIREFOX.copy()        capabilities['platform'] = "WINDOWS"        capabilities['version'] = "10"        # Instantiate an instance of Remote WebDriver with the desired capabilities.        driver = webdriver.Remote(desired_capabilities=capabilities,                                  command_executor=selenium_grid_url)    Note: Always use '.copy()' on the DesiredCapabilities object to avoid the side    effects of altering the Global class instance.    """    FIREFOX = {        "browserName": "firefox",        "version": "",        "platform": "ANY",        "javascriptEnabled": True,        "marionette": True,    }    INTERNETEXPLORER = {        "browserName": "internet explorer",        "version": "",        "platform": "WINDOWS",        "javascriptEnabled": True,    }    EDGE = {        "browserName": "MicrosoftEdge",        "version": "",        "platform": "WINDOWS"    }    CHROME = {        "browserName": "chrome",        "version": "",        "platform": "ANY",        "javascriptEnabled": True,    }    OPERA = {        "browserName": "opera",        "version": "",        "platform": "ANY",        "javascriptEnabled": True,    }    SAFARI = {        "browserName": "safari",        "version": "",        "platform": "MAC",        "javascriptEnabled": True,    }    HTMLUNIT = {        "browserName": "htmlunit",        "version": "",        "platform": "ANY",    }    HTMLUNITWITHJS = {        "browserName": "htmlunit",        "version": "firefox",        "platform": "ANY",        "javascriptEnabled": True,    }    IPHONE = {        "browserName": "iPhone",        "version": "",        "platform": "MAC",        "javascriptEnabled": True,    }    IPAD = {        "browserName": "iPad",        "version": "",        "platform": "MAC",        "javascriptEnabled": True,    }    ANDROID = {        "browserName": "android",        "version": "",        "platform": "ANDROID",        "javascriptEnabled": True,    }    PHANTOMJS = {        "browserName": "phantomjs",        "version": "",        "platform": "ANY",        "javascriptEnabled": True,    }
翻译下：
Set of default supported desired capabilities.desired capabilities默认支持的设置。Use this as a starting point for creating a desired capabilities object forrequesting remote webdrivers for connecting to selenium server or selenium grid.使用该类为selenium server或selenium grid启动一个desired capabilities配置

对配置项进行解释
FIREFOX = {    "browserName": "firefox",  # 浏览器名称    "version": "",             # 操作系统版本    "platform": "ANY",         # 平台，这里可以是windows、linux、andriod等等    "javascriptEnabled": True, # 是否启用js    "marionette": True,        # 这个值没找对应的说明^_^  不解释了}

DesiredCapabilities示例
from selenium import webdriver# 本地启动selenium gridselenium_grid_url = "http://127.0.0.1:4444/wd/hub"# 创建一个DesiredCapabilities实例capabilities = DesiredCapabilities.FIREFOX.copy()capabilities['platform'] = "WINDOWS"  # 指定操作系统capabilities['version'] = "10"   # 指定操作系统版本# 连接到远程服务进行自动化测试driver = webdriver.Remote(desired_capabilities=capabilities,                          command_executor=selenium_grid_url)
总结
这里的本质就是基于selenium grid 构建分布式自动化测试，
而selenium grid根据测试脚本构建的DesiredCapabilities参数来决定将您的测试脚本分发到哪台机器或设备进行测试。