Chapter 3. Introduction to Virtual user generator (vugen)

In the previous article we discussed about different components of Loadrunner and how Loadrunner is used for performance testing.

This article gives you an overview of on of the Loadrunner component Virtual user generator or Vugen.

Virtual user generator ( Vugen)

The main purpose of any Load testing tool  is to replace human users with virtual users.
Vugen is that component of Loadrunner which is used to do so.
Vugen tool is used to create scripts. These scripts when executed emulates the real user action.

Opening Vugen from Start button

Vugen Workflow

• Identify which protocol to use based on client server communication mechanism and server architecture.
• Record the user action. Script will be generated after recording session consists of functions which emulates real user actions. ".usr" file will be generated after recording.
• Enhance your raw recording  using the concepts of parameterisation, correlation , error handling (These concepts will be covered in different articles).
• Replay the script and verify the script works exactly as intended.
• Use the script in test execution to simulate large user load on server.

Different types of vusers

Based on the communication between client and server Loadrunner supports a huge range of protocols. A script can be of single protocol or combination of different protocols.

In the vugen click on File menu and select New script and Solution to choose any required protocol.

Web - http/html is largely used protocol and in the future articles this protocol is used to explain different concepts of Loadrunner.

Vugen interface

Vugen consists of multiple panes and editor which enables user to create, record, replay and debug the script. The whole interface can be customized as per the user needs.

Editor Pane: This is where the user see, enhance , debug the script.

Bottom pane.

Bottom pane: It contains multiple tabs used usually to debug the script.

Left pane: Consists of solution explorer to switch between different/ different parts of the scripts.

Right pane: Consists of script properties and step toolbox panes.

What all the things Vugen can be used to do

All of these concepts will be covered in details in different articles.

• Record and playback script.
• Enhance and debug  script using correlation, parameterisation, error handling, transaction naming.
• Save/ open scripts.
• Connect to ALM and upload or download scripts to ALM.
• Insert Loadrunner or user defined functions and headers.
• Configure run-time settings.