fix: generate tunnel id only if starting sauce connect

When tunnelIdentifier is not explicitly configured, generate a random id only if starting sauce connect.

When the developer does not want to start sauce connect, it's more likely he is reusing some already running instance of sauce connect and it's more likely this instance is not using any tunnel id.

index.js

@@ -60,15 +60,20 @@ var SauceLabsBrowser = function(id, args, sauceConnect, /* config.sauceLabs */ c
 
   var username = process.env.SAUCE_USERNAME || args.username || config.username;
   var accessKey = process.env.SAUCE_ACCESS_KEY || args.accessKey || config.accessKey;
-  var tunnelIdentifier = args.tunnelIdentifier || config.tunnelIdentifier || 'karma' + Math.round(new Date().getTime() / 1000);
+  var tunnelIdentifier = args.tunnelIdentifier || config.tunnelIdentifier;
   var browserName = args.browserName + (args.version ? ' ' + args.version : '') +
                     (args.platform ? ' (' + args.platform + ')' : '') + ' on SauceLabs';
+  var startConnect = config.startConnect !== false;
   var log = logger.create('launcher.sauce');
 
   var self = this;
   var driver;
   var captured = false;
 
+  if (startConnect && !tunnelIdentifier) {
+    tunnelIdentifier = 'karma' + Math.round(new Date().getTime() / 1000);
+  }
+
   this.id = id;
   this.name = browserName;
 
@@ -116,7 +121,7 @@ var SauceLabsBrowser = function(id, args, sauceConnect, /* config.sauceLabs */ c
   };
 
   this.start = function(url) {
-    if (config.startConnect !== false) {
+    if (startConnect) {
       sauceConnect.start(username, accessKey, tunnelIdentifier).then(function() {
         start(url);
       });