問題描述：
因使用uiautomator2跑android7.0以上版本經常報錯，原來用的appium1.8.1，所以就想升級一下appium試試看能不能解決。更新appium1.9.1成功後需要重新build WDA，但遇到一個問題，報錯：
'CocoaAsyncSocket/CocoaAsyncSocket.h' file not found。
解決辦法：
1. 確認appium依賴都已安裝
輸入appium-doctor發現是沒有安裝Xcode Command Line Tools
xxxxxxx$ appium -v
1.9.1
xxxxxxx$ appium-doctor
info AppiumDoctor Appium Doctor v.1.4.3
info AppiumDoctor ### Diagnostic starting ###
info AppiumDoctor ✔ The Node.js binary was found at: /usr/local/n/versions/node/10.4.0/bin/node
info AppiumDoctor ✔ Node version is 10.4.0
info AppiumDoctor ✔ Xcode is installed at: /Applications/Xcode.app/Contents/Developer
WARN AppiumDoctor ✖ Xcode Command Line Tools are NOT installed!
info AppiumDoctor ✔ DevToolsSecurity is enabled.
info AppiumDoctor ✔ The Authorization DB is set up properly.
info AppiumDoctor ✔ Carthage was found at: /usr/local/bin/carthage
info AppiumDoctor ✔ HOME is set to: /Users/liuming
info AppiumDoctor ✔ ANDROID_HOME is set to: /Users/liuming/Desktop/mobile_autotest/adt-bundle-mac/sdk
info AppiumDoctor ✔ JAVA_HOME is set to: /Library/Java/JavaVirtualMachines/jdk1.8.0_131.jdk/Contents/Home
info AppiumDoctor ✔ adb exists at: /Users/liuming/Desktop/mobile_autotest/adt-bundle-mac/sdk/platform-tools/adb
info AppiumDoctor ✔ android exists at: /Users/liuming/Desktop/mobile_autotest/adt-bundle-mac/sdk/tools/android
info AppiumDoctor ✔ emulator exists at: /Users/liuming/Desktop/mobile_autotest/adt-bundle-mac/sdk/tools/emulator
info AppiumDoctor ✔ Bin directory of $JAVA_HOME is set
info AppiumDoctor ### Diagnostic completed, one fix needed. ###
info AppiumDoctor
info AppiumDoctor ### Fixing: ✖ Xcode Command Line Tools are NOT installed! ###
info AppiumDoctor The following command need be executed: xcode-select --install
? Fix it: (Use arrow keys)
❯ yes
no
always
never
command line tools安裝
1. 使用命令行xcode-select -install安裝。
2. 直接用命令行安裝的是最新的command line tools，如果需要安裝舊版本的，去下面網址中找對應版本：https://developer.apple.com/download/more/
卸載command line tools的方法：
1. 直接刪除這個文件夾/Library/Developer/CommandLineTools
2. 也可以用命令行刪除：sudo rm -rf /Library/Developer/CommandLineTools
2. 確認WDA依賴都已安裝：
* which appium查看appium所在路徑
* 進入appium安裝盤：/path/where/installed/bin/appium, 在以下路徑下找到WebDriverAgent
/usr/local/n/versions/node/10.4.0/lib/node_modules/appium/node_modules/appium-xcuitest-driver/WebDriverAgent
* 打開terminal到上面的目錄下, 執行以下命令來配置項目:
$ mkdir -p Resources/WebDriverAgent.bundle
$ ./Scripts/bootstrap.sh -d
用Xcode打開WebDriverAgent.xcodeproj，進行build。參考文章https://blog.csdn.net/yinshuilan/article/details/80626314