无法运行iphone 5s模拟器无法启动

Question

我正在尝试通过appium和xcode测试我的网站。每次我启动测试时，都会在终端中收到此错误：

 Failure/Error: app = Appium::Driver.new(env[:desired_caps]).start_driver
     Selenium::WebDriver::Error::WebDriverError:

和appium输出中的这个错误：

    info: [debug] Error: Command failed: /bin/sh -c xcrun --sdk iphonesimulator --show-sdk-version

        at ChildProcess.exithandler (child_process.js:751:12)
        at ChildProcess.emit (events.js:110:17)
        at maybeClose (child_process.js:1015:16)
        at Process.ChildProcess._handle.onexit (child_process.js:1087:5)
    info: [debug] Responding to client with error: {"status":33,"value":{"message":"A new session could not be created. (Original error: Command failed: /bin/sh -c xcrun --sdk iphonesimulator --show-sdk-version\n)","cause":{"killed":true,"code":null,"signal":"SIGTERM","cmd":"/bin/sh -c xcrun --sdk iphonesimulator --show-sdk-version"},"isOperational":true,"killed":true,"code":null,"signal":"SIGTERM","cmd":"/bin/sh -c xcrun --sdk iphonesimulator --show-sdk-version","origValue":"Command failed: /bin/sh -c xcrun --sdk iphonesimulator --show-sdk-version\n"},"sessionId":null}
    info: <-- POST /wd/hub/session 500 9640.148 ms - 525 

    error: Could not determine iOS SDK version

    error: Failed to start an Appium session, err was: Error: Command failed: /bin/sh -c xcrun --sdk iphonesimulator --show-sdk-version

这是我的环境文件

    ios = {
        browser: "safari",
        platform: "ios",
        type: "mobile",
        tag: "ios",
        desired_caps: {
            caps: {  
                platformName: 'iOS',  
                platformVersion: '8.1',  
                deviceName: 'iPhone 5s',  
                browserName: 'Safari',
            }
        }
    }

这是我传递的规范：

    require './spec/spec_helper'
    require './spec/environments'
    require 'selenium-webdriver'
    require 'appium_lib'
    require_relative "../../spec/page_objects/home_page"

    @environments.each do |env|

      feature "Signing in to ArtWare" do

        app = nil

        if env[:type] == "computer"

          before(:all) do
            app = AbstractPage.new(Selenium::WebDriver.for(("#{env[:browser]}").to_sym))
          end

        elsif env[:type] == "mobile"

          before(:all) do
            app = Appium::Driver.new(env[:desired_caps]).start_driver
            Appium.promote_appium_methods Object

          end

        end



        it "In #{env[:platform]} app should let user in with a valid account and password", "#{env[:tag]}".to_sym do
          signInConfirmation = app
            .navigateToAppRoot
            .navigateToSignIn
            .fillInEmail('murat@breakthrough.com')
            .fillInPassword('asdfasdf')
            .submitSignInForm

          notice = signInConfirmation.getNoticeConfimation
          expect(notice).to eq('Signed in successfully.')
        end

        it "In #{env[:platform]} app should let user logout" do
          logoutConfirmation = app.logoutUser

          notice = logoutConfirmation.getNoticeConfimation
          expect(notice).to eq('Signed out successfully.')
        end


        it "In #{env[:platform]} app should not let use in with an invalid account", "#{env[:tag]}".to_sym do
          invalidEmailAlert = app
            .navigateToAppRoot
            .navigateToSignIn
            .fillInEmail('invalid@breakthrough.com')
            .fillInPassword('asdfasdf')
            .submitInvalidSignInForm

          alert = invalidEmailAlert.getInvalidSignInAlert
          expect(alert).to eq("Invalid email or password.")
        end

        it "In #{env[:platform]} app should not let user in with an invalid password", "#{env[:tag]}".to_sym do
          invalidEmailAlert = app
            .navigateToAppRoot
            .navigateToSignIn
            .fillInEmail('murat@breakthrough.com')
            .fillInPassword('incorrect')
            .submitInvalidSignInForm

          alert = invalidEmailAlert.getInvalidSignInAlert
          expect(alert).to eq("Invalid email or password.")
        end


        after(:all) do
          app.quit
        end

      end
    end