Performance testing is the practice of evaluating how a system performs in terms of responsiveness and stability under a particular workload. Performance tests are typically executed to examine speed, robustness, reliability, and application size.
The Apache JMeter™ application is open-source software, a 100% pure Java application designed to load test functional behavior and measure performance.
JMeter has the ability to performance test many different applications/server/protocol types.
Significantly –
- Web – HTTP, HTTPS
- UI – Browser
A load test enables us to measure response time when we apply load to the system to check the application’s breaking point. JMeter can be used to perform load testing for an API (without any additional coding) as well as to perform the UI load testing (with Selenium scripts) where it uses the browser to perform the user actions which are configured. UI Load testing is very important for any application where we expect more users to access the application at a single point in time. We should be able to analyze the load testing results and perform necessary improvements to achieve expected response times.
Performing load testing with a single machine is not ideal as there will be parallel browser sessions opened and the machine will soon reach its maximum capacity (Memory as well as CPU).
Also Performing load testing with a single machine is not ideal as in reality, different user will access the application from different machine.
So recommended method of performing UI load test using JMeter is to club it with API.
In this we scale up the no. of users sending HTTP request to the mid-tier thus increasing the load. Next use JMeter Selenium WebDriver Sample to mimic user interaction with one Browser and thus measure response time under heavy load.
To understand how API performance tests are done using JMeter, please read the blog – ‘BASIC API Performance Test using JMeter‘