it's all about the Performance Testing
The Controller is LoadRunner’s tool that lets you create and control LoadRunner scenarios. A scenario defines the events that occur during each testing session. It controls the number of users to emulate, the actions they perform, and the machines on which they run their emulations. You use scenarios to create load tests to check the reliability and strength of your servers. For details about load tests, see the Load Testing Overview.
The following are the primary items that you define in your scenario:
When you open the Controller for the first time, it prompts you to select a type of scenario: goal-oriented or manual.
During a scenario run, the Controller runs Vuser scripts or system/unit tests. Vuser scripts are tests scripts created with the LoadRunner Virtual User Generator.
System/Unit tests refer to NUnit, JUnit or some Java-based browser automation tests created in external development environments, such as Microsoft Visual Studio or Eclipse. You can work in your native application and prepare unit tests in binary form, such as .dll or .java files, and then run them from the Controller.
Note: For more best practice information, see the LoadRunner Best Practices Forum.
LoadRunner add-ins allow you to integrate the LoadRunner API with MS Visual Studio or Eclipse, and run tests from your native environment. For details, see the section on Additional Components in the LoadRunner Installation Guide.
The Controller’s opening dialog box prompts you to select the scripts and/or system/unit tests to include in the scenario.
All of your selections, along with the test paths, are saved in a scenario file (.lrs). You define all of the other aspects of your scenario in the Controller’s Design tab.
In the Controller, you define a number of Vusers (excluding GUI Vusers) to generate load on a server by submitting input directly to the server. Vusers do not operate client applications—they access the server using LoadRunner API functions. These API functions emulate the input from an actual application.
Because Vusers are not reliant on client software, you can use Vusers to test server performance even before the client software has been developed. Since Vusers do not have a user interface, the amount of system resources required is minimal. This allows you to run large numbers of Vusers on a single workstation.
The following example illustrates the use of Vusers in a scenario: Suppose that you have a Web-based database server that maintains your customer information. The information is accessed by numerous customer service personnel who are located throughout the country. The server receives the queries, processes the requests, and returns responses via the Web to field personnel.
You want to test the response times of the entire system when numerous service personnel simultaneously access the server. Using LoadRunner, you could create a scenario with several hundred Vusers, each one accessing the server database. The Vusers enable you to emulate and measure the performance of your database and Web servers under the load of many users.
To emulate the Vusers, you create a script to define their actions. A Vuser script includes functions that control the script execution and specify the input that the Vuser submits to the server. For more information, .
For the database server example above, you could create a Vuser script that performs the following actions: