Software load testing

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The term load testing or stress testing is used in different ways in the professional software testing community. Load testing generally refers to the practice of modeling the expected usage of a software program by simulating multiple users accessing the program concurrently. [1] As such, this testing is most relevant for multi-user systems; often one built using a client/server model, such as web servers. However, other types of software systems can also be load tested. For example, a word processor or graphics editor can be forced to read an extremely large document; or a financial package can be forced to generate a report based on several years' worth of data. The most accurate load testing simulates actual use, as opposed to testing using theoretical or analytical modeling.

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Load testing lets you measure your website's quality of service (QOS) performance based on actual customer behavior. Nearly all the load testing tools and frameworks follow the classical load testing paradigm: when customers visit your website, a script recorder records the communication and then creates related interaction scripts. A load generator tries to replay the recorded scripts, which could possibly be modified with different test parameters before replay. In the replay procedure, both the hardware and software statistics will be monitored and collected by the conductor, these statistics include the CPU, memory, disk IO of the physical servers and the response time, the throughput of the system under test (SUT), etc. And at last, all these statistics will be analyzed and a load testing report will be generated.

Load and performance testing analyzes software intended for a multi-user audience by subjecting the software to different numbers of virtual and live users while monitoring performance measurements under these different loads. Load and performance testing is usually conducted in a test environment identical to the production environment before the software system is permitted to go live.

Objectives of load testing: - To ensure that the system meets performance benchmarks; - To determine the breaking point of the system; - To test the way the product reacts to load-induced downtimes.

As an example, a website with shopping cart capability is required to support 100 concurrent users broken out into the following activities:

A test analyst can use various load testing tools to create these VUsers and their activities. Once the test has started and reached a steady-state, the application is being tested at the 100 VUser loads as described above. The application's performance can then be monitored and captured.

The specifics of a load test plan or script will generally vary across organizations. For example, in the bulleted list above, the first item could represent 25 VUsers browsing unique items, random items, or a selected set of items depending upon the test plan or script developed. However, all load test plans attempt to simulate system performance across a range of anticipated peak workflows and volumes. The criteria for passing or failing a load test (pass/fail criteria) are generally different across organizations as well. There are no standards specifying acceptable load testing performance metrics.

A common misconception is that load testing software provides record and playback capabilities like regression testing tools. Load testing tools analyze the entire OSI protocol stack whereas most regression testing tools focus on GUI performance. For example, a regression testing tool will record and playback a mouse click on a button on a web browser, but a load testing tool will send out hypertext the web browser sends after the user clicks the button. In a multiple-user environment, load testing tools can send out hypertext for multiple users with each user having a unique login ID, password, etc.

The popular load testing tools available also provide insight into the causes for slow performance. There are numerous possible causes for slow system performance, including, but not limited to, the following:

Load testing is especially important if the application, system, or service will be subject to a service level agreement or SLA.

Load testing is performed to determine a system's behavior under both normal and anticipated peak load conditions. It helps to identify the maximum operating capacity of an application as well as any bottlenecks and determine which element is causing degradation. When the load placed on the system is raised beyond normal usage patterns to test the system's response at unusually high or peak loads, it is known as stress testing. The load is usually so great that error conditions are the expected result, but there is no clear boundary when an activity ceases to be a load test and becomes a stress test.

The term "load testing" is often used synonymously with concurrency testing, software performance testing, reliability testing, and volume testing for specific scenarios. All of these are types of non-functional testing that are not part of functionality testing used to validate suitability for use of any given software.

User experience under load test

In the example above, while the device under test (DUT) is under production load - 100 VUsers, run the target application. The performance of the target application here would be the User Experience Under Load. It describes how fast or slow the DUT responds, and how satisfied or how the user actually perceives performance.

Browser-level vs. protocol-level users

Historically, all load testing was performed with automated API tests that simulated traffic through concurrent interactions at the protocol layer (often called protocol level users or PLUs). With the advance of containers and cloud infrastructure, the option is now present to test with real browsers (often called browser level users or BLUs). [2] Each approach has its merits for different types of applications, but generally, browser-level users will be more akin to the real traffic that a website will experience and provide a more realistic load profile and response time measurement. [3] BLUs are certainly a more expensive way of running tests and cannot work with all types of applications, specifically those that are not accessible through a web browser like a desktop client or API-based application. [4]

Load testing tools

Tool nameCompany nameLicenseTypePricingFocusNotes
Apache JMeter Apache Software Foundation Apache License  2.0LocalFreeJava desktop application for load testing and performance measurement.
BlazeMeter Perforce Software, Inc Proprietary Cloud-basedFree version, demo, paid plan, contact for pricingWebsite, web app, mobile, database, and other scenariosScalable load up to 200,000 concurrent simulated browser users from across eight geographical locations. Can also be used for integration and functional testing.
Blitz (discontinued in 2018) Spirent Communications Proprietary Cloud-basedTrial availableWebsites, mobile, and REST APIsIt allows to simulate of up to 50,000 simultaneous virtual users from different worldwide locations.
Flood Tricentis APAC Pty Ltd Proprietary Cloud-basedFree plan, paid plan, contact for pricingBrowser based load testing, APIs and protocol driven applicationsScalable load up to millions of concurrent users from all geographic regions available on AWS and Azure, plus on-premise deployments. Pricing is based on Virtual User Hours consumed each month. [5] [6]
Gatling Gatling Corp Apache License  2.0Local, cloud-basedFree version, demo, paid plan, contact for pricingJava web applicationsPortable HTML reports.
HammerDB GPLv3 LocalFreeDatabasesDatabase load testing and benchmarking tool.
Loader.io SendGrid, Inc Proprietary Cloud-basedFree plan, paid plan, contact for pricingWeb applications and API
LoadRunner Micro Focus Proprietary Local, Cloud-basedFree community edition; other: demo, free trial, contact for pricingPrimarily used for executing large numbers of tests (or a large number of virtual users) concurrently. Can be used for unit and integration testing as well.
LoadUI (integrated now in ReadyAPI) SmartBear Software EUPL LocalDemo availableCross-platform load testing tool, targeted mainly at web services. Integrates with soapUI.
Locust Open source MIT License Local, cloud-basedFreePython based framework with load tests expressed in regular code
Login VSI Login VSI, Inc. Proprietary LocalDemo, contact for pricingVirtual windows desktops workloads
NeoLoad Neotys Proprietary Local, cloud-basedFree trial, demo, contact for pricingWeb and mobileLoad can be generated from local agents or from the cloud.
OpenSTA CYRANO GNU General Public License  2.0LocalFreeWeb serverUtilizes a distributed software architecture based on CORBA. OpenSTA binaries available for Windows.
Parasoft SOAtest Parasoft Proprietary Local, cloud-basedDemo, contact for pricingPerformance testing tool that verifies functionality and performance under load. Supports SOAtest tests, JUnits, lightweight socket-based components. Detects concurrency issues.
Rational Performance Tester IBM Proprietary Local, cloud-basedContact for pricingEclipse-based large-scale performance testing tool primarily used for executing large volume performance tests to measure system response time for server-based applications.
Siege Open source  GPLv3  or laterLocalFreeWeb serversSupports basic authentication, cookies, HTTP, HTTPS and FTP protocols.
Silk Performer Micro Focus Proprietary Local, cloud-basedFree trial, contact for pricingApplication performance tool with cloud and local virtual agents. Supports most protocols and applications. Licensed.
SoapUI SmartBear Software EUPL Version 1.1 LocalFree
Test Studio Progress Telerik Proprietary LocalFree trial, demo, paid planAssess how the website would perform if visited by a large number of users at the same time.
Tsung Open Source GPL-2.0 LocalFreeWeb servers, Databases, XMPPIt can be used to stress HTTP, WebDAV, SOAP, PostgreSQL, MySQL, LDAP, MQTT and Jabber/XMPP servers.
Visual Studio Enterprise edition (deprecated after Visual Studio 2019) Microsoft Proprietary LocalPaid planVisual Studio Enterprise edition includes a load test tool that enables a developer to execute a variety of tests (web, unit, etc...) with a combination of configurations to simulate real user load. [7] Microsoft announced[ when? ] that its web performance and load test functionality was deprecated after Visual Studio 2019.
Vegeta MIT License LocalFreeHTTP applications
WebLOAD RadView Software Ltd Proprietary Local, cloud-basedFree trial, demo, contact for pricingWeb and Mobile applications and APILoad testing tool for web and mobile applications including Web Dashboard for performance test analysis. Used for large-scale loads which can be generated also from the cloud. Licensed.

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<span class="mw-page-title-main">Software testing</span> Checking software against a standard

Software testing is the act of checking whether software satisfies expectations.

<span class="mw-page-title-main">Web browser</span> Software used to access websites

A web browser is an application for accessing websites. When a user requests a web page from a particular website, the browser retrieves its files from a web server and then displays the page on the user's screen. Browsers are used on a range of devices, including desktops, laptops, tablets, and smartphones. In 2020, an estimated 4.9 billion people have used a browser. The most-used browser is Google Chrome, with a 64% global market share on all devices, followed by Safari with 19%.

In software quality assurance, performance testing is in general a testing practice performed to determine how a system performs in terms of responsiveness and stability under a particular workload. It can also serve to investigate, measure, validate or verify other quality attributes of the system, such as scalability, reliability and resource usage.

In computing, stress testing can be applied to either hardware or software. It is used to determine the maximum capability of a computer system and is often used for purposes such as scaling for production use and ensuring reliability and stability. Stress tests typically involve running a large amount of resource-intensive processes until the system either crashes or nearly does so.

<span class="mw-page-title-main">Load testing</span> Process of putting demand on a system and measuring its response

Load testing is the process of putting demand on a structure or system and measuring its response.

Web development is the work involved in developing a website for the Internet or an intranet. Web development can range from developing a simple single static page of plain text to complex web applications, electronic businesses, and social network services. A more comprehensive list of tasks to which Web development commonly refers, may include Web engineering, Web design, Web content development, client liaison, client-side/server-side scripting, Web server and network security configuration, and e-commerce development.

In software testing, test automation is the use of software separate from the software being tested to control the execution of tests and the comparison of actual outcomes with predicted outcomes. Test automation can automate some repetitive but necessary tasks in a formalized testing process already in place, or perform additional testing that would be difficult to do manually. Test automation is critical for continuous delivery and continuous testing.

<span class="mw-page-title-main">Apache JMeter</span> Open-source performance testing software

Apache JMeter is an Apache project that can be used as a load testing tool for analyzing and measuring the performance of a variety of services, with a focus on web applications.

<span class="mw-page-title-main">LoadRunner</span> Software testing tool

LoadRunner is a software testing tool from OpenText. It is used to test applications, measuring system behavior and performance under load.

<span class="mw-page-title-main">IBM TPNS</span> Test automation tool developed by IBM

Teleprocessing Network Simulator (TPNS) is an IBM licensed program, first released in 1976 as a test automation tool to simulate the end-user activity of network terminal(s) to a mainframe computer system, for functional testing, regression testing, system testing, capacity management, benchmarking and stress testing.

Selenium is an open source umbrella project for a range of tools and libraries aimed at supporting browser automation. It provides a playback tool for authoring functional tests across most modern web browsers, without the need to learn a test scripting language. It also provides a test domain-specific language (Selenese) to write tests in a number of popular programming languages, including JavaScript (Node.js), C#, Groovy, Java, Perl, PHP, Python, Ruby and Scala. Selenium runs on Windows, Linux, and macOS. It is open-source software released under the Apache License 2.0.

Performance engineering encompasses the techniques applied during a systems development life cycle to ensure the non-functional requirements for performance will be met. It may be alternatively referred to as systems performance engineering within systems engineering, and software performance engineering or application performance engineering within software engineering.

Stress testing is a software testing activity that determines the robustness of software by testing beyond the limits of normal operation. Stress testing is particularly important for "mission critical" software, but is used for all types of software. Stress tests commonly put a greater emphasis on robustness, availability, and error handling under a heavy load, than on what would be considered correct behavior under normal circumstances.

Web testing is software testing that focuses on web applications. Complete testing of a web-based system before going live can help address issues before the system is revealed to the public. Issues may include the security of the web application, the basic functionality of the site, its accessibility to disabled and fully able users, its ability to adapt to the multitude of desktops, devices, and operating systems, as well as readiness for expected traffic and number of users and the ability to survive a massive spike in user traffic, both of which are related to load testing.

InfinityDB is an all-Java embedded database engine and client/server DBMS with an extended java.util.concurrent.ConcurrentNavigableMap interface that is deployed in handheld devices, on servers, on workstations, and in distributed settings. The design is based on a proprietary lockless, concurrent, B-tree architecture that enables client programmers to reach high levels of performance without risk of failures.

<span class="mw-page-title-main">Gatling (software)</span>

Gatling is a load- and performance-testing framework based on Scala, Akka and Netty. The first stable release was published on January 13, 2012. In 2015, Gatling's founder, Stéphane Landelle, created a company, dedicated to the development of the open-source project. According to Gatling Corp's official blog, Gatling was downloaded more than 1,000,000 times (2021). In June 2016, Gatling officially presented Gatling FrontLine, Gatling's Enterprise Version with additional features.

<span class="mw-page-title-main">Test Studio</span> Software test automation tool

Progress Telerik Test Studio is a Windows-based software test automation tool for web and desktop that supports functional testing, software performance testing, load testing and RESTful API testing developed by Telerik. The tool ships with a plugin for Visual Studio and a standalone app that use the same repositories and file formats. Test Studio supports HTML, AJAX, Silverlight, ASP.NET MVC, JavaScript, WPF, Angular, React, ASP.NET AJAX, ASP.NET Core, and Blazor. Any application that runs on .NET 5, .NET Core, .NET 6 or higher can be automated with Test Studio. Test Studio supports cross-browser testing for Internet Explorer, Firefox, Microsoft Edge, and Chrome.

<span class="mw-page-title-main">WebLOAD</span> Software testing tool

WebLOAD is load testing tool, performance testing, stress test web applications. This web and mobile load testing and analysis tool is from RadView Software. Load testing tool WebLOAD combines performance, scalability, and integrity as a single process for the verification of web and mobile applications. It can simulate hundreds of thousands of concurrent users making it possible to test large loads and report bottlenecks, constraints, and weak points within an application.

Flood IO is a load testing platform that executes globally-distributed performance tests from open source tools, including JMeter, Gatling, and Selenium. It also runs test plans written with Ruby JMeter, an open source RubyGem.

References

  1. ↑ Wescott, Bob (2013). The Every Computer Performance Book, Chapter 6: Load Testing. CreateSpace. ISBN   978-1482657753.
  2. ↑ Platz, Wolfgang. "The future of load testing is BLU". InfoWorld. Retrieved 2018-11-23.
  3. ↑ "We're All Load Testers Now (Maybe) - DevOps.com". DevOps.com. 2018-02-08. Retrieved 2018-11-23.
  4. ↑ "How to Perform Load Testing With Real Browsers Using Flood Element?". geekflare.com. 2018-11-17. Retrieved 2018-11-23.
  5. ↑ Erinle, Bayo (2014). JMeter Cookbook. Packt Publishing. ISBN   978-1783988280.
  6. ↑ Erinle, Bayo (2015). Performance Testing with JMeter. Packt Publishing. ISBN   978-1784394813.
  7. ↑ "Load Testing ASP.NET Applications with Visual Studio 2010". Eggheadcafe.com. Retrieved 2013-01-13.
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