Allow using a custom Agent with http.HttpClient.

Change tests to use an Agent with a single socket
instead http.globalAgent for consistent behavior
between node v0.10.x and v0.11.y (y >= 7):

node v0.11.4 changed
http.globalAgent.maxSockets = Inifinity (from 5)
and v0.11.7 changed the http module to only send
“Connection: keep-alive” when necessary.

javascript/node/selenium-webdriver/http/index.js

@@ -28,15 +28,20 @@ var base = require('../_base'),
  * A {@link webdriver.http.Client} implementation using Node's built-in http
  * module.
  * @param {string} serverUrl URL for the WebDriver server to send commands to.
+ * @param {http.Agent=} opt_agent The agent to use for each request.
+ *     Defaults to {@code http.globalAgent}.
  * @constructor
  * @implements {webdriver.http.Client}
  */
-var HttpClient = function(serverUrl) {
+var HttpClient = function(serverUrl, opt_agent) {
   var parsedUrl = url.parse(serverUrl);
   if (!parsedUrl.hostname) {
     throw new Error('Invalid server URL: ' + serverUrl);
   }
 
+  /** @private {http.Agent} */
+  this.agent_ = opt_agent;
+
   /**
    * Base options for each request.
    * @private {!Object}
@@ -66,13 +71,17 @@ HttpClient.prototype.send = function(httpRequest, callback) {
     path += httpRequest.path;
   }
 
-  sendRequest({
+  var options = {
     method: httpRequest.method,
     host: this.options_.host,
     port: this.options_.port,
     path: path,
     headers: httpRequest.headers
-  }, callback, data);
+  };
+  if (this.agent_) {
+    options.agent = this.agent_;
+  }
+  sendRequest(options, callback, data);
 };
 
 

javascript/node/selenium-webdriver/test/http/http_test.js

@@ -14,6 +14,7 @@
 // limitations under the License.
 
 var assert = require('assert');
+var http = require('http');
 
 var HttpClient = require('../../http').HttpClient;
 var HttpRequest = require('../../_base').require('webdriver.http.Request');
@@ -52,7 +53,10 @@ describe('HttpClient', function() {
     var request = new HttpRequest('GET', '/echo');
     request.headers['Foo'] = 'Bar';
 
-    var client = new HttpClient(server.url());
+    var agent = new http.Agent();
+    agent.maxSockets = 1;  // Only making 1 request.
+
+    var client = new HttpClient(server.url(), agent);
     return promise.checkedNodeCall(client.send.bind(client, request))
         .then(function(response) {
           assert.equal(200, response.status);