Selenium RC与safari问题 - Selenium :: WebDriver :: Error :: UnknownError：Executor尚未启动

我正在尝试使用Selenium RC打开safari . 但是，Safari实例已创建并保持请求连接模式（SafariDriver在ws：// localhost：3078 / wd请求连接） .

require "selenium-webdriver"
caps = Selenium::WebDriver::Remote::Capabilities.safari
browser = Selenium::WebDriver.for :remote, :url=>"http://localhost:4444/wd/hub",    :desired_capabilities=>caps

上面的东西挂起并失败 - Selenium :: WebDriver :: Error :: UnknownError：来自[remote server] com.google.common.base.Preconditions（Preconditions.java）的Executor尚未启动（java.lang.IllegalStateException） ）：145：在 checkState' from [remote server] org.openqa.selenium.safari.SafariDriverCommandExecutor(SafariDriverCommandExecutor.java):123:in 执行'来自[远程服务器] org.openqa.selenium.remote.RemoteWebDriver（RemoteWebDriver.java）：432：in execute' from [remote server] org.openqa.selenium.remote.RemoteWebDriver(RemoteWebDriver.java):140:in startSession'from [remote server] org.openqa.selenium.remote.RemoteWebDriver（RemoteWebDriver） .j：）： <init>' from [remote server] org.openqa.selenium.safari.SafariDriver(SafariDriver.java):33:in '来自[remote server] sun.reflect.NativeConstructorAccessorImpl（NativeConstructorAccessorImpl.java）： - 2：in newInstance0' from [remote server] sun.reflect.NativeConstructorAccessorImpl(NativeConstructorAccessorImpl.java):39:in newInstance'from [remote server] sun.reflect.DelegatingConstructorAccessorImpl（DelegatingConstructorAccessorImpl.java）：27： in newInstance' from [remote server] java.lang.reflect.Constructor(Constructor.java):513:in newInstance'from [remote server] java.lang.Class（Class.java）：355：in newInstance0' from [remote server] java.lang.Class(Class.java):308:in newInstance'from [remote server] org.openqa.selenium.remote.server.DefaultDriverFactory（DefaultDriverFactory.java）：61： in callConstructor' from [remote server] org.openqa.selenium.remote.server.DefaultDriverFactory(DefaultDriverFactory.java):52:in newInstance'来自[remote server] org.openqa.selenium.remote.serve r.DefaultSession $ BrowserCreator（DefaultSession.java）：197：在 call' from [remote server] org.openqa.selenium.remote.server.DefaultSession$BrowserCreator(DefaultSession.java):1:in 中调用'... 4级...来自[远程服务器] java.util.concurrent.ThreadPoolExecutor $ Worker（ThreadPoolExecutor.java）：908：在 run' from [remote server] java.lang.Thread(Thread.java):680:in 中运行'from /Users/demo/.rvm/gems/ruby-1.9.2-p180/gems/selenium-webdriver-2.24.0/lib/selenium/webdriver/remote/response.rb:52:in assert_ok' from /Users/demo/.rvm/gems/ruby-1.9.2-p180/gems/selenium-webdriver-2.24.0/lib/selenium/webdriver/remote/response.rb:15:in initialize'from /用户/ demo / .rvm / gems / ruby-1.9.2-p180 / gems / selenium-webdriver-2.24.0 / lib / selenium / webdriver / remote / http / common.rb:59:in new' from /Users/demo/.rvm/gems/ruby-1.9.2-p180/gems/selenium-webdriver-2.24.0/lib/selenium/webdriver/remote/http/common.rb:59:in create_response'来自/ Users /demo/.rvm/gems/ruby-1.9.2-p180/gems/selenium-webdriver-2.24.0/lib/selenium/webdriver/remote/http/default.rb:59:in request' from /Users/demo/.rvm/gems/ruby-1.9.2-p180/gems/selenium-webdriver-2.24.0/lib/selenium/webdriver/remote/http/common.rb:40:in call'from / Users / demo / .rvm / gems / ruby-1.9.2-p180 / gems / selenium-webdriver-2.24.0 / lib / selenium / webdriver / remote / bridge.rb：598：in raw_execute' from /Users/demo/.rvm/gems/ruby-1.9.2-p180/gems/selenium-webdriver-2.24.0/lib/selenium/webdriver/remote/bridge.rb:92:in create_session'from / Users / demo / . rvm / gems / ruby-1.9.2-p180 / gems / selenium-webdriver-2.24.0 / lib / selenium / webdriver / remote / bridge.rb:68:in initialize' from /Users/demo/.rvm/gems/ruby-1.9.2-p180/gems/selenium-webdriver-2.24.0/lib/selenium/webdriver/common/driver.rb:33:in new'from /Users/demo/.rvm/gems /ruby-1.9.2-p180/gems/selenium-webdriver-2.24.0 /lib/selenium/webdriver/common/driver.rb:33:in for' from /Users/demo/.rvm/gems/ruby-1.9.2-p180/gems/selenium-webdriver-2.24.0/lib/selenium/webdriver.rb:65:in for'from（irb）：7