selenium源码通读·9 |webdriver/common/desired_capabilities.py-DesiredCapabilities类分析

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·9 |webdriver/common/desired_capabilities.py-DesiredCapabilities类分析

1 源码目录

selenium/webdriver/common/desired_capabilities.py

2 功能描述

  • 根据测试代码中配置的DesiredCapabilities参数,来决定将测试代码分发到哪台node上进行测试;
  • 补充知识:我们需要了解下selenium grid

3 Selenium Grid介绍

3.1 是什么?

  • Selenium套件的一部分,它专门用于并行运行多个测试用例在不同的浏览器、操作系统和机器上;
  • Selenium Grid 主要使用 master-slaves (or hub-nodes) 理念 ,是一个 master/hub 和多个基于master/hub注册的子节点 slaves/nodes
  • 在master上基于不同的浏览器/系统运行测试用例时,master将会分发给适当的node运行;

3.2 什么时候用?

  • 同时在不同的浏览器、操作系统和机器上运行测试;
  • 用于兼容性测试;
  • 减少运行时间。

3.3 怎么用?

  • 启动Selenium Grid的三种方式,一种直接用命令行,另一种用JSON配置文件,最后一种docker启动。

3.3.1 命令行启动

简单说下步骤,详细的请查阅其他资料,运行hub机器为A,运行node机器为B。

  • 配置Java环境;
  • 浏览器;
  • 浏览器对应的driver;
  • 下载selenium server,将selenium-server-standalone-3.141.59.jar,机器A和机器B上;
  • 机器A上打开命令行,进入selenium server目录下,运行:
ava -jar selenium-server-standalone-3.141.59.jar -role hub -port 5566
  • 浏览器输入http://localhost:5566/grid/console
  • 机器B上打开命令行,进入selenium server目录下,运行:
java -jar selenium-server-standalone-3.141.59.jar -role node -hub http://192.168.1.100:5566/grid/register/ -port 5577
  • 刷新http://localhost:5566/grid/console
  • 运行测试脚本,将会看到在机器B上打开了Chrome浏览器,并会运行测试用例。

3.3.2 Json配置文件启动

  • 创建hub的Json配置文件;

  "port": 4444,
  "newSessionWaitTimeout": -1,
  "servlets" : [],
  "withoutServlets": [],
  "custom": ,
  "capabilityMatcher": "org.openqa.grid.internal.utils.DefaultCapabilityMatcher",
  "registry": "org.openqa.grid.internal.DefaultGridRegistry",
  "throwOnCapabilityNotPresent": true,
  "cleanUpCycle": 5000,
  "role": "hub",
  "debug": false,
  "browserTimeout": 0,
  "timeout": 1800

  • 以上代码保存为hub_config.json文件,放在 机器A上和selenium server相同的路径下;
  • 创建nodes的 Json配置文件;

  "capabilities":
  [
    
      "browserName": "firefox",
      "marionette": true,
      "maxInstances": 5,
      "seleniumProtocol": "WebDriver"
    ,
    
      "browserName": "chrome",
      "maxInstances": 5,
      "seleniumProtocol": "WebDriver"
    ,
    
      "browserName": "internet explorer",
      "platform": "WINDOWS",
      "maxInstances": 1,
      "seleniumProtocol": "WebDriver"
    ,
    
      "browserName": "safari",
      "technologyPreview": false,
      "platform": "MAC",
      "maxInstances": 1,
      "seleniumProtocol": "WebDriver"
    
  ],
  "proxy": "org.openqa.grid.selenium.proxy.DefaultRemoteProxy",
  "maxSession": 5,
  "port": -1,
  "register": true,
  "registerCycle": 5000,
  "hub": "http://这里是机器A的ip:4444",
  "nodeStatusCheckTimeout": 5000,
  "nodePolling": 5000,
  "role": "node",
  "unregisterIfStillDownAfter": 60000,
  "downPollingLimit": 2,
  "debug": false,
  "servlets" : [],
  "withoutServlets": [],
  "custom": 


  • 保存为node_config.json文件,放在机器B上和selenium server相同的路径下;
  • 机器A,运行:
java -jar selenium-server-standalone-3.141.59.jar -role hub -hubConfig hub_config.json
  • 机器B,运行:
java -jar selenium-server-standalone-3.141.59.jar -role node -nodeConfig node_config.json

3.3.3 docker启动

  • 安装docker;
  • 启动hub:
docker run -d -p 4444:4444 --name selenium-hub selenium/hub
  • 启动node,比如chrome浏览器;
docker run -d --link selenium-hub:hub selenium/node-chrome
  • 访问:http://localhost:4444/grid/console
  • 运行多个node:
docker run -d --link selenium-hub:hub selenium/node-chrome
  • 关闭docker-grid的命令:
docker stop $(docker ps -a -q), docker rm $(docker ps -a -q)

4 部分源码说明

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",
        "marionette": True,
        "acceptInsecureCerts": True,
    

    INTERNETEXPLORER = 
        "browserName": "internet explorer",
        "version": "",
        "platform": "WINDOWS",
    

    EDGE = 
        "browserName": "MicrosoftEdge",
        "version": "",
        "platform": "WINDOWS"
    
# 剩下的源码省略
  • 从源码看,下边均对浏览器系统等的说明:
browserName:浏览器
version:操作系统版本
platform:操作系统

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