Performance Testing is the process by which software is tested and tuned with the intent of realizing the required performance.
The performance testing part of performance engineering encompasses what’s commonly referred to as load, spike, and stress testing, as well as validating system performance. Performance can be classified into three main categories:
• Speed — Does the application respond quickly enough for the intended users?
• Scalability — Will the application handle the expected user load and beyond?
• Stability — Is the application stable under expected and unexpected user loads?
Why should you automate performance testing?
A well-constructed performance test answers questions such as:
• Does the application respond quickly enough for the intended users?
• Will the application handle the expected user load and beyond?
• Will the application handle the number of transactions required by the business?
• Is the application stable under expected and unexpected user loads?
By answering these questions, automated performance testing quantifies the impact of a change in business terms. This in turn makes clear the risks of deployment. An effective automated performance testing process helps you to make more informed release decisions, and prevents system downtime and availability problems.
What are the LoadRunner components?
LoadRunner contains the following components:
• The Virtual User Generator captures end-user business processes and creates an automated performance testing script, also known as a virtual user script.
• The Controller organizes, drives, manages, and monitors the load test.
• The Load Generators create the load by running virtual users.
• The Analysis helps you view, dissect, and compare the performance results.
• The Launcher provides a single point of access for all of the LoadRunner components.
A scenario is a file that defines the events that occur during each testing session, based on performance requirements.
In the scenario, LoadRunner replaces human users with virtual users or Vusers. Vusers emulate the actions of human users working with your application. A scenario can contain tens, hundreds, or even thousands of Vusers.
The actions that a Vuser performs during the scenario are described in a Vuser script. To measure the performance of the server, you define transactions. A transaction represents end-user business processes that you are interested in measuring.
Load Testing Process
Load testing typically consists of five phases: planning, script creation, scenario definition, scenario execution, and results analysis.
Plan Load Test: Define your performance testing requirements, for example, number of concurrent users, typical business processes and required response times.
Create Vuser Scripts: Capture the end-user activities into automated scripts.
Define a Scenario: Use the LoadRunner Controller to set up the load test environment.
Run a Scenario: Drive, manage, and monitor the load test from the LoadRunner Controller.
Analyze the Results: Use LoadRunner Analysis to create graphs and reports, and evaluate the performance.
Load Runner has good reporting features with which the user can easily analyze the performance test results.