If you have gone through the Selenium RC posts, you may have known that a Selenium Server need to be run as a prerequisite for running the Selenium RC Automation tests.
Why Selenium Server is required by Selenium RC ?
As Selenium RC doesn't make direct calls to browser. So it requires Selenium Server as a mediator between Selenium RC tests and Browsers.
So in order to run any Selenium RC Automation tests, we've to run the Selenium Server first.
Is Selenium Server required by Selenium WebDriver ?
Selenium Server is not required by Selenium WebDriver when we run the Selenium Automation tests on the same machine. (i.e. Browsers and Automation tests are on the same machine).
Why Selenium Server is not required when the Test Browsers and Automation Tests are on the same machine ?
Selenium WebDriver makes direct calls to the browser using each browser's native support for Test Automation.
We use FireFox Browsers native support in our Selenium Automation code in order to run our tests on Firefox Browser.
In the similar manner we use Native support of Browsers to run our tests on respective browsers.
Hence Selenium Server is not required for running Selenium Web Driver Automation tests on the same machine.
But, you may require Selenium Server for running Selenium WebDriver Automation tests on different machines (i.e. when the Selenium tests and Test Browsers are on different machines). This case may be possible only when implementing Selenium Grid where you have to run automation tests simultaneously on different machines to reduce time). Suppose you have 10 tests and each test takes a day to run. Then you may implement Selenium Grid to use 10 machines each running a single automation tests. Hence you will reduce the time from 10 days to 1 day.
So to conclude, like Selenium RC we are not going to run Selenium Server as a pre-requisite when the Selenium Tests and Test Browsers are on the same machine.
Please comment below to feedback or ask questions.
Selenium RC versus Selenium Web Driver will be explained in the next post.