When do you need to run tests on remote servers -

    1. When your server doesn't have web browser and your tests need web browser to run successfully, in this case you will have to move to some other server which has web browser installed or run test remotely on the server where web browser is already installed.
    2. Or you want to run same test on different web browsers, which are installed on different remote servers having different Operating Systems in parallel.

There are different approaches to address above mentioned problems.

Either you can use RemoteWebDriver Server to solve first mentioned problem above (which will help you to run test on remote server) Or in both the cases you can use Selenium GRID.

Please find details below -

The RemoteWebDriver is composed of two pieces: a client and a server. The client is your WebDriver test and the server is simply a Java servlet, which can be hosted in any modern JEE app server. The server will always run on the machine with the browser you want to test. There are two ways to user the server: command line or configured in code.

Once you have downloaded selenium-server-standalone-{VERSION}.jar place it on the computer with the browser you want to test. Then from the directory with the jar run the following

You can download 2.47.1 version directly or from here get the latest once (under Selenium Standalone Server section)

java -jar selenium-server-standalone-{VERSION}.jar

$ java -jar selenium-server-standalone-2.47.1.jar

23:04:53.282 INFO - Launching a standalone Selenium Server

23:04:53.619 INFO - Java: Oracle Corporation 25.60-b23

23:04:53.620 INFO - OS: Windows 7 6.1 amd64

23:04:53.628 INFO - v2.47.1, with Core v2.47.1. Built from revision 411b314

23:04:53.679 INFO - Driver class not found: com.opera.core.systems.OperaDriver

23:04:53.679 INFO - Driver provider com.opera.core.systems.OperaDriver is not registered

23:04:54.081 INFO - RemoteWebDriver instances should connect to: http://127.0.0.1:4444/wd/hub

23:04:54.081 INFO - Selenium Server is up and running

Please refer sample code below -

// We could use any driver here (I am using firefox driver)

DesiredCapabilities capabilities = DesiredCapabilities.firefox();

// ... but only if it supports javascript

// Make sure your browser supports javascript, otherwise you can't use RemoteWebDriver

capabilities.setJavascriptEnabled(true);

// Get a handle to the driver. This will throw an exception

// if a matching driver cannot be located

driver = new RemoteWebDriver(new URL("http://IP_ADDRESS_OF_REMOTE_SERVER:4444/wd/hub"), capabilities);

The caller is expected to terminate each session properly, calling either Selenium#stop() or WebDriver#quit.

The selenium-server keeps in-memory logs for each ongoing session, which are cleared when Selenium#stop() or WebDriver#quit is called. If you forget to terminate these sessions your server may leak memory. If you keep extremely long-running sessions you will probably need to stop/quit every now and then (or increase memory with -Xmx jvm option)

// If using WebDriver then

driver.quit();

// If using Selenium RC then

selenium.stop();

As I mentioned earlier, grid can be used if you want to do cross browser testing (and want to save time by running single tests on multiple servers at the same time), and also want to make sure your application is working fine on different Operating Systems as well.

There is no change in Client side code except that now each client can specify capabilities and based on that GRIDs assign nodes to the client to run the test.

Steps involved:

java -jar selenium-server-standalone-2.14.0.jar -role hub

Output:

$ java -jar selenium-server-standalone-2.47.1.jar -role hub

23:36:58.945 INFO - Launching Selenium Grid hub

2015-10-06 23:37:00.140:INFO:osjs.Server:jetty-7.x.y-SNAPSHOT

2015-10-06 23:37:00.164:INFO:osjsh.ContextHandler:started o.s.j.s.ServletContextHandler{/,null}

2015-10-06 23:37:00.172:INFO:osjs.AbstractConnector:Started SocketConnector@0.0.0.0:4444

23:37:00.173 INFO - Nodes should register to http://HUB_IP:4444/grid/register

23:37:00.173 INFO - Selenium Grid hub is up and running

java -jar selenium-server-standalone-2.14.0.jar -role node  -hub http://HUB_IP:4444/grid/register

Output :

$ java -jar selenium-server-standalone-2.47.1.jar -role node  -hub http://HUB_IP:4444/grid/register

23:30:33.509 INFO - Launching a Selenium Grid node

23:30:35.033 INFO - Java: Oracle Corporation 25.60-b23

23:30:35.034 INFO - OS: Windows 7 6.1 amd64

23:30:35.038 INFO - v2.47.1, with Core v2.47.1. Built from revision 411b314

23:30:35.068 INFO - Driver class not found: com.opera.core.systems.OperaDriver

23:30:35.068 INFO - Driver provider com.opera.core.systems.OperaDriver is not registered

23:30:35.094 INFO - Selenium Grid node is up and ready to register to the hub

23:30:35.113 INFO - Starting auto registration thread. Will try to register every 5000 ms.

23:30:35.114 INFO - Registering the node to the hub: http://HUB_IP:4444/grid/register

23:30:35.136 INFO - The node is registered to the hub and ready to use

HUB_IP = Server name / IP where Hub is running

// We could use any driver for our tests...

DesiredCapabilities capabilities = DesiredCapabilities.firefox();

// ... but only if it supports javascript

capabilities.setJavascriptEnabled(true);

// Get a handle to the driver. This will throw an exception

// if a matching driver cannot be located

driver = new RemoteWebDriver(new URL("http://HUB_IP:4444/wd/hub"), capabilities);

If multiple nodes are registered to Hub then, based on client's connection inputs, HUB identifies on which nodes this test should run

For e.g. assume we have HUB running and two nodes are registered (one has Firefox/Linux and other node has Windows/Internet Explorer).

When one client invoke test with DesiredCapabilities = IE then HUB knows where this test should be running, and it assigns Node with IE browser to that client to run tests… and if DesiredCapabilities = Firefox then Hub assigns a Linux server for running test.

I hope this helps you!

Please comment if you have any question regarding the same. Thanks!