As a non-functional software testing technique, load testing is conducted to assess the performance of a software application under varying load conditions. The testing helps QA professionals to identify the maximum amount of load or pressure an application can withstand. But the testers need complete the load tests within a stipulated amount of time and controlled lab conditions to assess the performance of the application accurately under both normal and peak conditions. That is why; most testers use load testing tools to assess the performance of the application regularly and repeatedly under varying loads. They also have option to take advantage of a number of open source load testing tools to assess the performance of the software regularly without increasing project overheads.
Understanding 8 Widely Used Open Source Load Testing Tools
1) The Grinder
Despite being a popular load testing tool, The Grinder is often described as the Java load testing tool. It can be used to load test any application with a Java API. But The Grinder supports major protocols like SOAP, HTTP and REST web services. It allows testers to write test scripts in Jython or Clojure, while providing centralized script editing and distribution feature. The users also have option to use data stored on files and databases, and generate test data on the fly. So it becomes easier for them to load test the software based on a variety of parameters.
Unlike other load testing tools, JMeter is designed as a desktop application with a graphical user interface. The Java-based tool further runs on any platform that supports the programming language. It further supports major web servers and protocols including HTTP, SOAP, REST web services, MangoDB, TCP, Mail and LDAP. The testers also have option to enhance test coverage by integrating JMeter with a number of commonly used build and continuous integration (CI) tools.
Tsung is designed as a distributed load testing tool. It supports most of the commonly used protocols including HTTP, SOAP, MySQL, PostgreSQL, WebDAV and LDAP. Tsung is also designed with features to assess the performance of IP based client/server applications by simulating the behaviour of a large number of users. As the testers have option to run Tsung on multiple machines, it becomes easier for them to simulate a large number of virtual users simultaneously.
The cross-platform load testing tool is written in Scala. It comes with a recorder that enables testers to record all user actions and simulate all probable user actions. So it becomes easier for them load test the applications by creating many test scenarios. Gatling further allows testers to modify and customize the test scenarios according to the requirements of the project. At the same time, Gatling also helps testers to generate clear, colourful and information test reports to facilitate decision making.
Locust is one of the popular user load testing tools for websites and web applications. It requires testers to write all test scenarios in Python programming language. The users also have option to run Locust on single or multiple machines. So it becomes easier for them to distribute load tests over several machines, and simulate a large number of users simultaneously. Locust further makes it easier for testers to generate real-time and relevant test results by providing an extensible web-based user interface.
6) Diesel Test
DieselTest is actually designed as a regression testing tool. So it is different from other traditional regression testing tools available in the market. As it supports only keyboard and mouse driven test scripts, the scripting support provided by DieselTest is not powerful. But the testers can Playback the test scripts to assess the performance of the software by simulating behaviour of real website visitors. They also have option to generate and analyze real-time test results.
OpenSTA is popular among testers as a flexible load testing tool. It enables testers to use and playback recorded scripts to assess the application’s performance regularly. At the same time, the testers also have option to edit the convert the recorded macro into a test script, make necessary changes to the script, and inject it as a hypertext stream. They can even use the tool to load test a variety of software applications. But the open source load testing tool looks dated as it was last updated in 2007.
OpenWebLoad is one of the simple and easy-to-use load testing tools available in the market. It can be used for assessing the performance of a web application under various loads. The testers also have option to use a command line to configure and execute load tests. OpenWebLoad further allows testers to monitor the impact of load optimization in an instant and realistic way. However, DieselTest is not being updated at regular intervals like other tools.
However, it is also important for the testers to pick the right open source load testing tools according to the nature and needs of the project. In addition to focusing on key features of various load testing tools, they also need to compare the tools based on test scenario and infrastructure. They can even consider using multiple tools to assess the performance of the applications accurately under a variety of loads.