Editing Software testing (section)

== Categories ==
{{Anchor|Testing types}}
{{Main|Software testing tactics}}

Testing can be categorized many ways.<ref>{{Cite book |last1=Kaner |first1=Cem |url=https://archive.org/details/lessonslearnedso00kane |title=Lessons Learned in Software Testing: A Context-Driven Approach |last2=Bach |first2=James |last3=Pettichord |first3=Bret |publisher=Wiley |year=2001 |isbn=978-0-471-08112-8 |pages=[https://archive.org/details/lessonslearnedso00kane/page/n55 31]–43 |url-access=limited}}</ref>

=== Automated testing ===
{{Excerpt|Test automation|paragraphs=1|only=paragraph}}

=== Levels ===

Software testing can be categorized into levels based on how much of the [[software system]] is the focus of a test.<ref name="Computer.org">{{Cite book |title=Guide to the Software Engineering Body of Knowledge |publisher=IEEE Computer Society |year=2014 |isbn=978-0-7695-5166-1 |editor-last=Bourque |editor-first=Pierre |series=3.0 |chapter=Chapter 5 |access-date=January 2, 2018 |editor-last2=Fairley |editor-first2=Richard E. |chapter-url=https://www.computer.org/web/swebok/v3}}</ref><ref name="BourqueSWEBOK14-4">{{Cite book |title=SWEBOK v3.0: Guide to the Software Engineering Body of Knowledge |publisher=IEEE |year=2014 |isbn=978-0-7695-5166-1 |editor-last=Bourque, P. |pages=4–1–4–17 |chapter=Chapter 4: Software Testing |access-date=July 13, 2018 |editor-last2=Fairley, R.D. |chapter-url=http://www4.ncsu.edu/~tjmenzie/cs510/pdf/SWEBOKv3.pdf |archive-date=June 19, 2018 |archive-url=https://web.archive.org/web/20180619003324/http://www4.ncsu.edu/~tjmenzie/cs510/pdf/SWEBOKv3.pdf |url-status=dead }}</ref><ref name="DooleySoftware11">{{Cite book |last=Dooley, J. |url=https://books.google.com/books?id=iOqP9_6w-18C&pg=PA193 |title=Software Development and Professional Practice |publisher=APress |year=2011 |isbn=978-1-4302-3801-0 |pages=193–4}}</ref><ref name="WiegersCreating13">{{Cite book |last=Wiegers, K. |url=https://books.google.com/books?id=uVsUAAAAQBAJ&pg=PA212 |title=Creating a Software Engineering Culture |publisher=Addison-Wesley |year=2013 |isbn=978-0-13-348929-3 |pages=211–2}}</ref>

==== Unit testing ====
{{Excerpt|Unit testing|paragraphs=1|only=paragraph}}

==== Integration testing ====
{{Excerpt|Integration testing|paragraphs=1|only=paragraph}}

==== System testing ====
{{Excerpt|System testing|paragraphs=1|only=paragraph}}

=== Static, dynamic, and passive testing ===

There are many approaches to software testing. [[Code review|Reviews]], [[software walkthrough|walkthrough]]s, or [[Software inspection|inspections]] are referred to as static testing, whereas executing programmed code with a given set of [[test case]]s is referred to as [[dynamic testing]].<ref name="GrahamFoundations08">{{Cite book |last1=Graham, D. |url=https://books.google.com/books?id=Ss62LSqCa1MC&pg=PA57 |title=Foundations of Software Testing |last2=Van Veenendaal, E. |last3=Evans, I. |publisher=Cengage Learning |year=2008 |isbn=978-1-84480-989-9 |pages=57–58}}</ref><ref name="OberkampfVerif10">{{Cite book |last1=Oberkampf, W.L. |url=https://books.google.com/books?id=7d26zLEJ1FUC&pg=PA155 |title=Verification and Validation in Scientific Computing |last2=Roy, C.J. |publisher=Cambridge University Press |year=2010 |isbn=978-1-139-49176-1 |pages=154–5}}</ref>

Static testing is often implicit, like proofreading, plus when programming tools/text editors check source code structure or compilers (pre-compilers) check syntax and data flow as [[static program analysis]]. Dynamic testing takes place when the program itself is run. Dynamic testing may begin before the program is 100% complete in order to test particular sections of code and are applied to discrete [[Function (computer science)|functions]] or modules.<ref name="GrahamFoundations08" /><ref name="OberkampfVerif10" /> Typical techniques for these are either using [[Method stub|stubs]]/drivers or execution from a [[debugger]] environment.<ref name="OberkampfVerif10" />

Static testing involves [[software verification|verification]], whereas dynamic testing also involves [[software validation|validation]].<ref name="OberkampfVerif10" />

Passive testing means verifying the system's behavior without any interaction with the software product. Contrary to active testing, testers do not provide any test data but look at system logs and traces. They mine for patterns and specific behavior in order to make some kind of decisions.<ref>{{Cite book |last1=Lee |first1=D. |last2=Netravali |first2=A.N. |last3=Sabnani |first3=K.K. |last4=Sugla |first4=B. |last5=John |first5=A. |title=Proceedings 1997 International Conference on Network Protocols |chapter=Passive testing and applications to network management |year=1997 |publisher=IEEE Comput. Soc |pages=113–122 |doi=10.1109/icnp.1997.643699 |isbn=978-0-8186-8061-8 |s2cid=42596126}}</ref> This is related to offline [[runtime verification]] and [[log analysis]].

=== Exploratory ===
{{Excerpt|Exploratory testing|paragraph=1}}

=== Preset testing vs adaptive testing ===
The type of testing strategy to be performed depends on whether the tests to be applied to the IUT should be decided before the testing plan starts to be executed (preset testing<ref>{{Cite journal |last1=Lee |first1=D. | last2=Yannakakis |first2=M. |date=1996 |title=Principles and methods of testing finite state machines-a survey |url=https://doi.org/10.1109/5.533956 |journal=Proceedings of the IEEE |volume=84 |issue=8 |pages=1090–1123|doi=10.1109/5.533956 |url-access=subscription }}</ref>) or whether each input to be applied to the IUT can be dynamically dependent on the outputs obtained during the application of the previous tests (adaptive testing<ref>{{Cite book |last1=Petrenko|first1=A. |last2=Yevtushenko |first2=N. |title=In Testing Software and Systems: 23rd IFIP WG 6.1 International Conference, ICTSS 2011, Paris, France, November 7-10 |chapter= Adaptive testing of deterministic implementations specified by nondeterministic FSMs |series=Lecture Notes in Computer Science | chapter-url=https://doi.org/10.1007/978-3-642-24580-0_12 |year=2011 |volume=7019 |publisher=Springer Berlin Heidelberg |pages=162–178 |doi=10.1007/978-3-642-24580-0_12 |isbn=978-3-642-24579-4 }}</ref><ref>{{Cite book |last1=Petrenko|first1=A. |last2=Yevtushenko |first2=N. |title=In 2014 IEEE 15th International Symposium on High-Assurance Systems Engineering |chapter= Adaptive testing of nondeterministic systems with FSM | url=https://doi.org/10.1109/HASE.2014.39 |year=2014 |publisher=IEEE |pages=224–228 |doi=10.1109/HASE.2014.39 |isbn=978-1-4799-3466-9 }}</ref>).

=== Black/white box ===

Software testing can often be divided into white-box and black-box. These two approaches are used to describe the point of view that the tester takes when designing test cases. A hybrid approach called grey-box that includes aspects of both boxes may also be applied to software testing methodology.<ref name="LimayeSoftware09">{{Cite book |last=Limaye, M.G. |url=https://books.google.com/books?id=zUm8My7SiakC&pg=PA108 |title=Software Testing |publisher=Tata McGraw-Hill Education |year=2009 |isbn=978-0-07-013990-9 |pages=108–11}}</ref><ref name="SalehSoftware09">{{Cite book |last=Saleh, K.A. |url=https://books.google.com/books?id=N69KPjBEWygC&pg=PA224 |title=Software Engineering |publisher=J. Ross Publishing |year=2009 |isbn=978-1-932159-94-3 |pages=224–41}}</ref>

==== White-box testing ====
{{Main|White-box testing}}

[[File:White Box Testing Approach.png|alt=White Box Testing Diagram|thumb|White box testing diagram]]

White-box testing (also known as clear box testing, glass box testing, transparent box testing, and structural testing) verifies the internal structures or workings of a program, as opposed to the functionality exposed to the end-user. In white-box testing, an internal perspective of the system (the source code), as well as programming skills are used to design test cases. The tester chooses inputs to exercise paths through the code and determines the appropriate outputs.<ref name="LimayeSoftware09" /><ref name="SalehSoftware09" /> This is analogous to testing nodes in a circuit, e.g., [[in-circuit test]]ing (ICT).

While white-box testing can be applied at the [[unit testing|unit]], [[integration testing|integration]], and [[system testing|system]] levels of the software testing process, it is usually done at the unit level.<ref name="AmmannIntro16" /> It can test paths within a unit, paths between units during integration, and between subsystems during a system–level test. Though this method of test design can uncover many errors or problems, it might not detect unimplemented parts of the specification or missing requirements.

Techniques used in white-box testing include:<ref name="SalehSoftware09" /><ref name="EverettSoftware07">{{Cite book |last1=Everatt, G.D. |title=Software Testing: Testing Across the Entire Software Development Life Cycle |last2=McLeod Jr., R. |publisher=John Wiley & Sons |year=2007 |isbn=978-0-470-14634-7 |pages=99–121 |chapter=Chapter 7: Functional Testing}}</ref>

* [[API testing]] – testing of the application using public and private [[application programming interfaces|APIs]] (application programming interfaces)
* [[Code coverage]] – creating tests to satisfy some criteria of code coverage (for example, the test designer can create tests to cause all statements in the program to be executed at least once)
* [[Fault injection]] methods – intentionally introducing faults to gauge the efficacy of testing strategies
* [[Mutation testing]] methods
* [[Static testing]] methods

Code coverage tools can evaluate the completeness of a test suite that was created with any method, including black-box testing. This allows the software team to examine parts of a system that are rarely tested and ensures that the most important [[function points]] have been tested.<ref name="CornettCode96">{{Cite web |last=Cornett |first=Steve |date=c. 1996 |title=Code Coverage Analysis |url=https://www.bullseye.com/coverage.html#intro |access-date=November 21, 2017 |publisher=Bullseye Testing Technology |at=Introduction}}</ref> Code coverage as a [[software metric]] can be reported as a percentage for:<ref name="LimayeSoftware09" /><ref name="CornettCode96" /><ref name="BlackPragmatic11">{{Cite book |last=Black, R. |url=https://books.google.com/books?id=n-bTHNW97kYC&pg=PA44 |title=Pragmatic Software Testing: Becoming an Effective and Efficient Test Professional |publisher=John Wiley & Sons |year=2011 |isbn=978-1-118-07938-6 |pages=44–6}}</ref>

:* ''Function coverage'', which reports on functions executed
:* ''Statement coverage'', which reports on the number of lines executed to complete the test
:* ''Decision coverage'', which reports on whether both the True and the False branch of a given test has been executed

100% statement coverage ensures that all code paths or branches (in terms of [[control flow]]) are executed at least once. This is helpful in ensuring correct functionality, but not sufficient since the same code may process different inputs correctly or incorrectly.<ref>As a simple example, the [[C (programming language)|C]] function <syntaxhighlight lang="C" inline>int f(int x){return x*x-6*x+8;}</syntaxhighlight> consists of only one statement. All tests against a specification <syntaxhighlight lang="C" inline>f(x)>=0</syntaxhighlight> will succeed, except if <syntaxhighlight lang="C" inline>x=3</syntaxhighlight> happens to be chosen.</ref>

==== Black-box testing ====
{{Main|Black-box testing}}
[[File:Black box diagram.svg|thumb|Black box diagram]]

Black-box testing (also known as functional testing) describes designing test cases without knowledge of the implementation, without reading the source code. The testers are only aware of what the software is supposed to do, not how it does it.<ref name="Patton">{{Cite book |last=Patton |first=Ron |url=https://archive.org/details/softwaretesting0000patt |title=Software Testing |publisher=Sams Publishing |year=2005 |isbn=978-0-672-32798-8 |edition=2nd |location=Indianapolis}}</ref> Black-box testing methods include: [[equivalence partitioning]], [[boundary value analysis]], [[all-pairs testing]], [[state transition table]]s, [[decision table]] testing, [[fuzz testing]], [[model-based testing]], [[use case]] testing, [[exploratory testing]], and specification-based testing.<ref name="LimayeSoftware09" /><ref name="SalehSoftware09" /><ref name="BlackPragmatic11" />

Specification-based testing aims to test the functionality of software according to the applicable requirements.<ref>{{Cite thesis |last=Laycock |first=Gilbert T. |title=The Theory and Practice of Specification Based Software Testing |degree=dissertation |publisher=Department of Computer Science, [[University of Sheffield]] |url=https://www.cs.le.ac.uk/people/glaycock/thesis.pdf |year=1993 |access-date=January 2, 2018}}</ref> This level of testing usually requires thorough [[test case]]s to be provided to the tester, who then can simply verify that for a given input, the output value (or behavior), either "is" or "is not" the same as the expected value specified in the test case. Test cases are built around specifications and requirements, i.e., what the application is supposed to do. It uses external descriptions of the software, including specifications, requirements, and designs, to derive test cases. These tests can be [[functional testing|functional]] or [[non-functional testing|non-functional]], though usually functional. Specification-based testing may be necessary to assure correct functionality, but it is insufficient to guard against complex or high-risk situations.<ref>{{Cite journal |last=Bach |first=James |author-link=James Bach |date=June 1999 |title=Risk and Requirements-Based Testing |url=https://www.satisfice.com/articles/requirements_based_testing.pdf |journal=Computer |volume=32 |issue=6 |pages=113–114 |access-date=August 19, 2008}}</ref>

Black box testing can be used to any level of testing although usually not at the unit level.<ref name="AmmannIntro16" />

'''Component interface testing'''

Component interface testing is a variation of [[black-box testing]], with the focus on the data values beyond just the related actions of a subsystem component.<ref name="MathurFound11-63">{{Cite book |last=Mathur, A.P. |url=https://books.google.com/books?id=hyaQobu44xUC&pg=PA18 |title=Foundations of Software Testing |publisher=Pearson Education India |year=2011 |isbn=978-81-317-5908-0 |page=63}}</ref> The practice of component interface testing can be used to check the handling of data passed between various units, or subsystem components, beyond full integration testing between those units.<ref name="Clapp">{{Cite book |last=Clapp |first=Judith A. |url=https://books.google.com/books?id=wAq0rnyiGMEC&pg=PA313 |title=Software Quality Control, Error Analysis, and Testing |year=1995 |isbn=978-0-8155-1363-6 |page=313 |publisher=William Andrew |access-date=January 5, 2018}}</ref><ref name="Mathur">{{Cite book |last=Mathur |first=Aditya P. |url=https://books.google.com/books?id=yU-rTcurys8C&pg=PR38 |title=Foundations of Software Testing |publisher=Pearson Education India |year=2007 |isbn=978-81-317-1660-1 |page=18}}</ref> The data being passed can be considered as "message packets" and the range or data types can be checked for data generated from one unit and tested for validity before being passed into another unit. One option for interface testing is to keep a separate log file of data items being passed, often with a timestamp logged to allow analysis of thousands of cases of data passed between units for days or weeks. Tests can include checking the handling of some extreme data values while other interface variables are passed as normal values.<ref name=Clapp/> Unusual data values in an interface can help explain unexpected performance in the next unit.

===== Visual testing =====

The aim of visual testing is to provide developers with the ability to examine what was happening at the point of software failure by presenting the data in such a way that the developer can easily find the information he or she requires, and the information is expressed clearly.<ref>{{Cite thesis |last=Lönnberg |first=Jan |title=Visual testing of software |date=October 7, 2003 |degree=MSc |publisher=Helsinki University of Technology |url=https://www.cs.hut.fi/~jlonnber/VisualTesting.pdf |access-date=January 13, 2012}}</ref><ref>{{Cite magazine |last=Chima |first=Raspal |title=Visual testing |url=http://www.testmagazine.co.uk/2011/04/visual-testing |magazine=TEST Magazine |archive-url=https://web.archive.org/web/20120724162657/http://www.testmagazine.co.uk/2011/04/visual-testing/ |archive-date=July 24, 2012 |access-date=January 13, 2012}}</ref>

At the core of visual testing is the idea that showing someone a problem (or a test failure), rather than just describing it, greatly increases clarity and understanding. Visual testing, therefore, requires the recording of the entire test process – capturing everything that occurs on the test system in video format. Output videos are supplemented by real-time tester input via picture-in-a-picture webcam and audio commentary from microphones.

Visual testing provides a number of advantages. The quality of communication is increased drastically because testers can show the problem (and the events leading up to it) to the developer as opposed to just describing it, and the need to replicate test failures will cease to exist in many cases. The developer will have all the evidence he or she requires of a test failure and can instead focus on the cause of the fault and how it should be fixed.

[[Ad hoc testing]] and [[exploratory testing]] are important methodologies for checking software integrity because they require less preparation time to implement, while the important bugs can be found quickly.<ref name="LewisSoftware16">{{Cite book |last=Lewis, W.E. |url=https://books.google.com/books?id=fgaBDd0TfT8C&pg=PA68 |title=Software Testing and Continuous Quality Improvement |publisher=CRC Press |year=2016 |isbn=978-1-4398-3436-7 |edition=3rd |pages=68–73}}</ref> In ad hoc testing, where testing takes place in an improvised impromptu way, the ability of the tester(s) to base testing off documented methods and then improvise variations of those tests can result in a more rigorous examination of defect fixes.<ref name="LewisSoftware16" /> However, unless strict documentation of the procedures is maintained, one of the limits of ad hoc testing is lack of repeatability.<ref name="LewisSoftware16" />

{{further|Graphical user interface testing}}

==== Grey-box testing ====
{{main|Gray box testing}}

Grey-box testing (American spelling: gray-box testing) involves using knowledge of internal data structures and algorithms for purposes of designing tests while executing those tests at the user, or black-box level. The tester will often have access to both "the source code and the executable binary."<ref name="RansomeCore13">{{Cite book |last1=Ransome, J. |url=https://books.google.com/books?id=MX5cAgAAQBAJ&pg=PA140 |title=Core Software Security: Security at the Source |last2=Misra, A. |publisher=CRC Press |year=2013 |isbn=978-1-4665-6095-6 |pages=140–3}}</ref> Grey-box testing may also include [[Reverse coding|reverse engineering]] (using dynamic code analysis) to determine, for instance, boundary values or error messages.<ref name="RansomeCore13" /> Manipulating input data and formatting output do not qualify as grey-box, as the input and output are clearly outside of the "black box" that we are calling the system under test. This distinction is particularly important when conducting [[integration testing]] between two modules of code written by two different developers, where only the interfaces are exposed for the test.

By knowing the underlying concepts of how the software works, the tester makes better-informed testing choices while testing the software from outside. Typically, a grey-box tester will be permitted to set up an isolated testing environment with activities, such as seeding a [[database]]. The tester can observe the state of the product being tested after performing certain actions such as executing [[SQL]] statements against the database and then executing queries to ensure that the expected changes have been reflected. Grey-box testing implements intelligent test scenarios based on limited information. This will particularly apply to data type handling, [[exception handling]], and so on.<ref name="ref4">{{Cite web |title=SOA Testing Tools for Black, White and Gray Box |url=http://www.crosschecknet.com/soa_testing_black_white_gray_box.php |archive-url=https://web.archive.org/web/20181001010542/http://www.crosschecknet.com:80/soa_testing_black_white_gray_box.php |archive-date=October 1, 2018 |access-date=December 10, 2012 |publisher=Crosscheck Networks |type=white paper}}</ref>

With the concept of grey-box testing, this "arbitrary distinction" between black- and white-box testing has faded somewhat.<ref name="AmmannIntro16">{{Cite book |last1=Ammann, P. |url=https://books.google.com/books?id=58LeDQAAQBAJ&pg=PA26 |title=Introduction to Software Testing |last2=Offutt, J. |publisher=Cambridge University Press |year=2016 |isbn=978-1-316-77312-3 |page=26}}</ref>

=== Installation testing ===
{{Excerpt|Installation testing|paragraph=1}}

=== Compatibility testing ===
{{main|Compatibility testing}}

A common cause of software failure (real or perceived) is a lack of its [[Computer compatibility|compatibility]] with other [[application software]], [[operating system]]s (or operating system [[Software versioning|version]]s, old or new), or target environments that differ greatly from the original (such as a [[computer terminal|terminal]] or [[GUI]] application intended to be run on the [[Desktop metaphor|desktop]] now being required to become a [[Web application]], which must render in a [[Web browser]]). For example, in the case of a lack of [[backward compatibility]], this can occur because the programmers develop and test software only on the latest version of the target environment, which not all users may be running. This results in the unintended consequence that the latest work may not function on earlier versions of the target environment, or on older hardware that earlier versions of the target environment were capable of using. Sometimes such issues can be fixed by proactively [[Abstraction (computer science)|abstracting]] operating system functionality into a separate program [[Modular programming|module]] or [[Library (computing)|library]].

=== Smoke and sanity testing ===
{{main|Smoke testing (software)}}

[[Sanity testing]] determines whether it is reasonable to proceed with further testing.

[[Smoke testing (software)|Smoke testing]] consists of minimal attempts to operate the software, designed to determine whether there are any basic problems that will prevent it from working at all. Such tests can be used as [[build verification test]].

=== Regression testing ===
{{Main|Regression testing}}

Regression testing focuses on finding defects after a major code change has occurred. Specifically, it seeks to uncover [[software regression]]s, as degraded or lost features, including old bugs that have come back. Such regressions occur whenever software functionality that was previously working correctly, stops working as intended. Typically, regressions occur as an [[unintended consequence]] of program changes, when the newly developed part of the software collides with the previously existing code. Regression testing is typically the largest test effort in commercial software development,<ref>{{Cite book |last1=Ammann |first1=Paul |url=https://books.google.com/books?id=leokXF8pLY0C&pg=PA215 |title=Introduction to Software Testing |last2=Offutt |first2=Jeff |date=January 28, 2008 |publisher=[[Cambridge University Press]] |isbn=978-0-521-88038-1 |page=215 |access-date=November 29, 2017}}</ref> due to checking numerous details in prior software features, and even new software can be developed while using some old test cases to test parts of the new design to ensure prior functionality is still supported.

Common methods of regression testing include re-running previous sets of test cases and checking whether previously fixed faults have re-emerged. The depth of testing depends on the phase in the release process and the [[risk management|risk]] of the added features. They can either be complete, for changes added late in the release or deemed to be risky, or be very shallow, consisting of positive tests on each feature, if the changes are early in the release or deemed to be of low risk.

=== Acceptance testing ===

{{Main|Acceptance testing}}

Acceptance testing is system-level testing to ensure the software meets customer expectations.<ref name="LewisSoftware16-2" /><ref name="BorbaTesting10">{{Cite book |last1=Machado, P. |title=Testing Techniques in Software Engineering |last2=Vincenzi, A. |last3=Maldonado, J.C. |publisher=Springer Science & Business Media |year=2010 |isbn=978-3-642-14334-2 |editor-last=Borba, P. |pages=13–14 |chapter=Chapter 1: Software Testing: An Overview |editor-last2=Cavalcanti, A. |editor-last3=Sampaio, A. |editor-last4=Woodcook, J. |chapter-url=https://books.google.com/books?id=ZOHrm02GFCEC&pg=PA13}}</ref><ref name="ClappSoftware95">{{Cite book |last1=Clapp, J.A. |url=https://books.google.com/books?id=wAq0rnyiGMEC&pg=PA254 |title=Software Quality Control, Error Analysis, and Testing |last2=Stanten, S.F. |last3=Peng, W.W. |publisher=Nova Data Corporation |year=1995 |isbn=978-0-8155-1363-6 |page=254 |display-authors=et al}}</ref><ref name=":0">{{Cite web |title=ISTQB CTFL Syllabus 2018 |url=https://istqb-main-web-prod.s3.amazonaws.com/media/documents/ISTQB-CTFL_Syllabus_2018_v3.1.1.pdf |website=ISTQB - International Software Testing Qualifications Board |url-status=live |archive-url=https://web.archive.org/web/20220324091506/https://istqb-main-web-prod.s3.amazonaws.com/media/documents/ISTQB-CTFL_Syllabus_2018_v3.1.1.pdf |archive-date=2022-03-24 |access-date=2022-04-11}}</ref>

Acceptance testing may be performed as part of the hand-off process between any two phases of development.{{Citation needed|date= January 2008}}

Tests are frequently grouped into these levels by where they are performed in the software development process, or by the level of specificity of the test.<ref name=":0" />

* User acceptance testing (UAT)
* Operational acceptance testing (OAT)
* Contractual and regulatory acceptance testing
* Alpha and beta testing

Sometimes, UAT is performed by the customer, in their environment and on their own hardware.

OAT is used to conduct operational readiness (pre-release) of a product, service or system as part of a [[quality management system]]. OAT is a common type of non-functional software testing, used mainly in [[software development]] and [[software maintenance]] projects. This type of testing focuses on the operational readiness of the system to be supported, or to become part of the production environment. Hence, it is also known as operational readiness testing (ORT) or [[operations readiness and assurance]] (OR&A) testing. [[Functional testing]] within OAT is limited to those tests that are required to verify the ''non-functional'' aspects of the system.

In addition, the software testing should ensure that the portability of the system, as well as working as expected, does not also damage or partially corrupt its operating environment or cause other processes within that environment to become inoperative.<ref>{{Cite web |last=Woods |first=Anthony J. |date=June 5, 2015 |title=Operational Acceptance – an application of the ISO 29119 Software Testing standard |url=https://www.scribd.com/document/257086897/Operational-Acceptance-Test-White-Paper-2015-Capgemini |access-date=January 9, 2018 |publisher=Capgemini Australia |type=Whitepaper}}</ref>

Contractual acceptance testing is performed based on the contract's acceptance criteria defined during the agreement of the contract, while regulatory acceptance testing is performed based on the relevant regulations to the software product. Both of these two tests can be performed by users or independent testers. Regulation acceptance testing sometimes involves the regulatory agencies auditing the test results.<ref name=":0" />

=== Alpha testing ===
Alpha testing is simulated or actual operational testing by potential users/customers or an independent test team at the developers' site. Alpha testing is often employed for off-the-shelf software as a form of internal acceptance testing before the software goes to beta testing.<ref>{{Cite web |title=Standard Glossary of Terms used in Software Testing |url=https://www.astqb.org/documents/Glossary-of-Software-Testing-Terms-v3.pdf |access-date=January 9, 2018 |publisher=International Software Testing Qualifications Board |version=Version 3.1}}</ref>

=== Beta testing ===
{{See also|Software release life cycle#Beta}}

Beta testing comes after alpha testing and can be considered a form of external [[user acceptance testing]]. Versions of the software, known as [[beta version]]s, are released to a limited audience outside of the programming team known as beta testers. The software is released to groups of people so that further testing can ensure the product has few faults or [[computer bug|bug]]s. Beta versions can be made available to the open public to increase the [[Feedback#In organizations|feedback]] field to a maximal number of future users and to deliver value earlier, for an extended or even indefinite period of time ([[perpetual beta]]).<ref>{{Cite web |last=O'Reilly |first=Tim |date=September 30, 2005 |title=What is Web 2.0 |url=https://www.oreilly.com/pub/a/web2/archive/what-is-web-20.html?page=4 |access-date=January 11, 2018 |publisher=O'Reilly Media |at=Section 4. End of the Software Release Cycle}}</ref>

=== Functional vs non-functional testing ===

[[Functional testing]] refers to activities that verify a specific action or function of the code. These are usually found in the code requirements documentation, although some development methodologies work from use cases or user stories. Functional tests tend to answer the question of "can the user do this" or "does this particular feature work."

[[Non-functional testing]] refers to aspects of the software that may not be related to a specific function or user action, such as [[scalability]] or other [[performance]], behavior under certain [[constraint (mathematics)|constraint]]s, or [[computer security|security]]. Testing will determine the breaking point, the point at which extremes of scalability or performance leads to unstable execution. Non-functional requirements tend to be those that reflect the quality of the product, particularly in the context of the suitability perspective of its users.

=== Continuous testing ===
{{Main|Continuous testing}}

Continuous testing is the process of executing [[test automation|automated tests]] as part of the software delivery pipeline to obtain immediate feedback on the business risks associated with a software release candidate.<ref name="essential">{{Cite web |last=Auerbach |first=Adam |date=August 3, 2015 |title=Part of the Pipeline: Why Continuous Testing Is Essential |url=https://www.techwell.com/techwell-insights/2015/08/part-pipeline-why-continuous-testing-essential |access-date=January 12, 2018 |website=TechWell Insights |publisher=TechWell Corp.}}</ref><ref name="stickym">{{Cite web |last=Philipp-Edmonds |first=Cameron |date=December 5, 2014 |title=The Relationship between Risk and Continuous Testing: An Interview with Wayne Ariola |url=http://www.stickyminds.com/interview/relationship-between-risk-and-continuous-testing-interview-wayne-ariola |access-date=January 16, 2018 |website=Stickyminds}}</ref> Continuous testing includes the validation of both [[functional requirements]] and [[non-functional requirements]]; the scope of testing extends from validating bottom-up requirements or user stories to assessing the system requirements associated with overarching business goals.<ref name="pnsqc">{{Cite conference |last1=Ariola |first1=Wayne |last2=Dunlop |first2=Cynthia |date=October 2015 |title=DevOps: Are You Pushing Bugs to Clients Faster? |url=http://uploads.pnsqc.org/2015/papers/t-007_Ariola_paper.pdf |conference=Pacific Northwest Software Quality Conference |access-date=January 16, 2018}}</ref><ref name="shift">{{Cite web |last=Auerbach |first=Adam |date=October 2, 2014 |title=Shift Left and Put Quality First |url=https://www.techwell.com/techwell-insights/2014/10/shift-left-and-put-quality-first |access-date=January 16, 2018 |website=TechWell Insights |publisher=TechWell Corp.}}</ref>

=== Destructive testing ===
{{Main|Destructive testing}}

Destructive testing attempts to cause the software or a sub-system to fail. It verifies that the software functions properly even when it receives invalid or unexpected inputs, thereby establishing the [[Robustness (computer science)|robustness]] of input validation and error-management routines.{{citation needed|date= July 2012}} [[Fault injection|Software fault injection]], in the form of [[Fuzz testing|fuzzing]], is an example of failure testing. Various commercial non-functional testing tools are linked from the [[Fault injection|software fault injection]] page; there are also numerous open-source and free software tools available that perform destructive testing.

{{further|Exception handling|Recovery testing}}

=== Software performance testing ===
{{Main|Software performance testing}}

Performance testing is generally executed to determine how a system or sub-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.

''[[Load testing#Software load testing|Load testing]]'' is primarily concerned with testing that the system can continue to operate under a specific load, whether that be large quantities of data or a large number of [[Load testing|users]]. This is generally referred to as software [[scalability]]. The related load testing activity of when performed as a non-functional activity is often referred to as ''endurance testing''. ''[[Volume testing]]'' is a way to test software functions even when certain components (for example a file or database) increase radically in size. ''[[Stress testing]]'' is a way to test reliability under unexpected or rare workloads. ''Stability testing'' (often referred to as load or endurance testing) checks to see if the software can continuously function well in or above an acceptable period.

There is little agreement on what the specific goals of performance testing are. The terms load testing, performance testing, [[scalability testing]], and volume testing, are often used interchangeably.

[[Real-time computing|Real-time software]] systems have strict timing constraints. To test if timing constraints are met, [[real-time testing]] is used.

=== Usability testing ===

[[Usability testing]] is to check if the user interface is easy to use and understand. It is concerned mainly with the use of the application. This is not a kind of testing that can be automated; actual human users are needed, being monitored by skilled [[User experience design#Interaction designers|UI designers]]. Usability testing can use structured models to check how well an interface works. The Stanton, Theofanos, and Joshi (2015) model looks at user experience, and the Al-Sharafat and Qadoumi (2016) model is for expert evaluation, helping to assess usability in digital applications.<ref>{{Cite journal |last=Taqi |first=Farwa |last2=Batool |first2=Syeda Hina |last3=Arshad |first3=Alia |date=2024-05-23 |title=Development and Validation of Cloud Applications Usability Development Scale |url=https://www.tandfonline.com/doi/full/10.1080/10447318.2024.2351715 |journal=International Journal of Human–Computer Interaction |language=en |pages=1–16 |doi=10.1080/10447318.2024.2351715 |issn=1044-7318|url-access=subscription }}</ref>

=== Accessibility testing ===

[[Accessibility]] testing is done to ensure that the software is accessible to persons with disabilities. Some of the common web accessibility tests are

* Ensuring that the color contrast between the font and the background color is appropriate
* Font Size
* Alternate Texts for multimedia content
* Ability to use the system using the computer keyboard in addition to the mouse.

==== Common standards for compliance ====
* [[Americans with Disabilities Act of 1990]]
* [[Section 508 Amendment to the Rehabilitation Act of 1973]]
* [[Web Accessibility Initiative]] (WAI) of the [[World Wide Web Consortium]] (W3C)

=== Security testing ===

[[Security testing]] is essential for software that processes confidential data to prevent [[Backdoor (computing)|system intrusion]] by [[Hacker (computer security)|hackers]].

The International Organization for Standardization (ISO) defines this as a "type of testing conducted to evaluate the degree to which a test item, and associated data and information, are protected so that unauthorised persons or systems cannot use, read or modify them, and authorized persons or systems are not denied access to them."<ref>{{Cite book |url=https://www.iso.org/standard/45142.html |title=ISO/IEC/IEEE 29119-1:2013 – Software and Systems Engineering – Software Testing – Part 1 – Concepts and Definitions |publisher=International Organization for Standardization |chapter=Section 4.38 |access-date=January 17, 2018}}</ref>

=== Internationalization and localization ===

Testing for [[internationalization and localization]] validates that the software can be used with different languages and geographic regions. The process of [[pseudolocalization]] is used to test the ability of an application to be translated to another language, and make it easier to identify when the localization process may introduce new bugs into the product.

Globalization testing verifies that the software is adapted for a new culture, such as different currencies or time zones.<ref>{{Cite web |title=Globalization Step-by-Step: The World-Ready Approach to Testing. Microsoft Developer Network |url=https://msdn.microsoft.com/en-us/goglobal/bb688148 |access-date=January 13, 2012 |publisher=Microsoft Developer Network |archive-url=https://web.archive.org/web/20120623050851/https://msdn.microsoft.com/en-us/goglobal/bb688148 |archive-date=June 23, 2012}}</ref>

Actual translation to human languages must be tested, too. Possible localization and globalization failures include:

* Some messages may be untranslated.
* Software is often localized by translating a list of [[String (computer science)|strings]] out of context, and the translator may choose the wrong translation for an ambiguous source string.
* Technical terminology may become inconsistent, if the project is translated by several people without proper coordination or if the translator is imprudent.
* Literal word-for-word translations may sound inappropriate, artificial or too technical in the target language.
* Untranslated messages in the original language may be [[Hard coding|hard coded]] in the source code, and thus untranslatable.
* Some messages may be created automatically at [[Run time (program lifecycle phase)|run time]] and the resulting string may be ungrammatical, functionally incorrect, misleading or confusing.
* Software may use a [[keyboard shortcut]] that has no function on the source language's [[keyboard layout]], but is used for typing characters in the layout of the target language.
* Software may lack support for the [[character encoding]] of the target language.
* Fonts and font sizes that are appropriate in the source language may be inappropriate in the target language; for example, [[CJK characters]] may become unreadable if the font is too small.
* A string in the target language may be longer than the software can handle. This may make the string partly invisible to the user or cause the software to crash or malfunction.
* Software may lack proper support for reading or writing [[bi-directional text]].
* Software may display images with text that was not localized.
* Localized operating systems may have differently named system [[configuration file]]s and [[environment variable]]s and different [[Date and time notation by country|formats for date]] and [[currency]].

=== Development testing ===
{{Main|Development testing}}

Development testing is a software development process that involves the synchronized application of a broad spectrum of defect prevention and detection strategies in order to reduce software development risks, time, and costs. It is performed by the software developer or engineer during the construction phase of the software development lifecycle. Development testing aims to eliminate construction errors before code is promoted to other testing; this strategy is intended to increase the quality of the resulting software as well as the efficiency of the overall development process.

Depending on the organization's expectations for software development, development testing might include [[static code analysis]], data flow analysis, metrics analysis, peer code reviews, unit testing, code coverage analysis, [[Requirements traceability|traceability]], and other software testing practices.

=== A/B testing ===
{{Main|A/B testing}}

A/B testing is a method of running a controlled experiment to determine if a proposed change is more effective than the current approach. Customers are routed to either a current version (control) of a feature, or to a modified version (treatment) and data is collected to determine which version is better at achieving the desired outcome.

=== Concurrent testing ===
{{Main|Concurrent testing}}

Concurrent or concurrency testing assesses the behaviour and performance of software and systems that use [[concurrent computing]], generally under normal usage conditions. Typical problems this type of testing will expose are deadlocks, race conditions and problems with shared memory/resource handling.

=== Conformance testing or type testing ===
{{Main|Conformance testing}}

In software testing, conformance testing verifies that a product performs according to its specified standards. Compilers, for instance, are extensively tested to determine whether they meet the recognized standard for that language.

=== Output comparison testing ===

Creating a display expected output, whether as [[File comparison|data comparison]] of text or screenshots of the UI,<ref name="Kaner2" />{{Rp|195}} is sometimes called snapshot testing or Golden Master Testing unlike many other forms of testing, this cannot detect failures automatically and instead requires that a human evaluate the output for inconsistencies.

=== Property testing ===
{{distinguish|property testing{{!}}property testing algorithms}}

Property testing is a testing technique where, instead of asserting that specific inputs produce specific expected outputs, the practitioner randomly generates many inputs, runs the program on all of them, and asserts the truth of some "property" that should be true for every pair of input and output. For example, every output from a serialization function should be accepted by the corresponding deserialization function, and every output from a sort function should be a monotonically increasing list containing exactly the same elements as its input.

Property testing libraries allow the user to control the strategy by which random inputs are constructed, to ensure coverage of degenerate cases, or inputs featuring specific patterns that are needed to fully exercise aspects of the implementation under test.

Property testing is also sometimes known as "generative testing" or "QuickCheck testing" since it was introduced and popularized by the Haskell library [[QuickCheck]].<ref>{{Cite book |chapter-url=https://dl.acm.org/doi/abs/10.1145/351240.351266 |series=Icfp '00 |pages=268–279 |doi=10.1145/351240.351266 |isbn=978-1-58113-202-1 |s2cid=5668071 |chapter=QuickCheck |title=Proceedings of the fifth ACM SIGPLAN international conference on Functional programming |date=2000 |last1=Claessen |first1=Koen |last2=Hughes |first2=John }}</ref>

=== Metamorphic testing===
{{Main|Metamorphic testing}}

Metamorphic testing (MT) is a property-based software testing technique, which can be an effective approach for addressing the test oracle problem and test case generation problem. The test oracle problem is the difficulty of determining the expected outcomes of selected test cases or to determine whether the actual outputs agree with the expected outcomes.

=== VCR testing ===

VCR testing, also known as "playback testing" or "record/replay" testing, is a testing technique for increasing the reliability and speed of regression tests that involve a component that is slow or unreliable to communicate with, often a third-party API outside of the tester's control. It involves making a recording ("cassette") of the system's interactions with the external component, and then replaying the recorded interactions as a substitute for communicating with the external system on subsequent runs of the test.

The technique was popularized in web development by the Ruby library [https://github.com/vcr/vcr vcr].