Backport some fixes from master branch

Author: robocoder

lib/WebDriver/AbstractWebDriver.php

@@ -149,7 +149,7 @@ protected function curl($requestMethod, $command, $parameters = null, $extraOpti
             );
         }
 
-        if (is_array($result) && !array_key_exists('status', $result) && !isset($result['value']['ready']) && ! isset($result['value']['error'])) {
+        if (is_array($result) && ! array_key_exists('status', $result) && ! array_key_exists('value', $result)) {
             throw WebDriverException::factory(
                 WebDriverException::CURL_EXEC,
                 'Payload received from webdriver is valid but unexpected json: ' . substr($rawResult, 0, 1000)
@@ -183,9 +183,12 @@ protected function curl($requestMethod, $command, $parameters = null, $extraOpti
 
         $sessionId = isset($result['sessionId'])
            ? $result['sessionId']
-           : (isset($value['webdriver.remote.sessionid'])
-               ? $value['webdriver.remote.sessionid']
-               : null
+           : (isset($value['sessionId'])
+               ? $value['sessionId']
+               : (isset($value['webdriver.remote.sessionid'])
+                   ? $value['webdriver.remote.sessionid']
+                   : null
+               )
            );
 
         return array(

lib/WebDriver/Exception.php

@@ -86,6 +86,7 @@ abstract class Exception extends \Exception
     const UNEXPECTED_PARAMETERS = -5;
     const INVALID_REQUEST = -6;
     const UNKNOWN_LOCATOR_STRATEGY = -7;
+    const W3C_WEBDRIVER_ERROR = -8;
 
     private static $errs = array(
 //      self::SUCCESS => array('Success', 'This should never be thrown!'),
@@ -136,12 +137,8 @@ abstract class Exception extends \Exception
     public static function factory($code, $message = null, $previousException = null)
     {
         // unknown error
-        if (!isset(self::$errs[$code])) {
-            if (trim($message) === '') {
-                $message = 'Unknown Error';
-            }
-
-            return new \Exception($message, $code, $previousException);
+        if (! isset(self::$errs[$code])) {
+            $code = self::UNKNOWN_ERROR;
         }
 
         $errorDefinition = self::$errs[$code];
@@ -150,6 +147,10 @@ public static function factory($code, $message = null, $previousException = null
             $message = $errorDefinition[1];
         }
 
+        if (! is_numeric($code)) {
+            $code = self::W3C_WEBDRIVER_ERROR;
+        }
+
         $className = __CLASS__ . '\\' . $errorDefinition[0];
 
         return new $className($message, $code, $previousException);