  }

instance Default XvfbConfig where
  def = XvfbConfig Nothing

defaultWdOptions :: FilePath -> FilePath -> WdOptions
defaultWdOptions toolsRoot runRoot = WdOptions toolsRoot runRoot (const False) def OnException Normal

data WdSession = WdSession { wdLabels :: [String]
                           , wdWebDriver :: (Handle, Handle, ProcessHandle, FilePath, FilePath, Maybe XvfbSession)
                           , wdOptions :: WdOptions
                           , wdSessionMap :: MVar [(Browser, W.WDSession)]