Shift-left testing: Difference between revisions

Revision as of 12:09, 27 October 2020

Revision as of 21:32, 14 December 2020

Line 2:

{{Orphan|date=May 2015}}

}}

'''Shift-left testing'''<ref>{{cite web|url=https://web.archive.org/web/20150905082941/https://insights.sei.cmu.edu/sei_blog/2015/03/four-types-of-shift-left-testing.html |title=Four Types of Shift Left Testing |author=Donald Firesmith | date=23 March 2015 |accessdateaccess-date=27 March 2015}}</ref> is an approach to [[software testing]] and [[system testing]] in which testing is performed earlier in the [[software development life cycle|lifecycle]] (i.e. moved left on the project timeline). It is the first half of the maxim "Test early and often."<ref>{{cite web|url=https://msdn.microsoft.com/en-us/library/vstudio/ee330950%28v=vs.110%29.aspx |title=Test Early and Often |author=Microsoft | date=2012 |accessdateaccess-date=27 March 2015}}</ref> It was coined by Larry Smith in 2001.<ref>{{Cite journal|last=Smith|first=Larry|date=September 2001|title=Shift-Left Testing|url=https://www.drdobbs.com/shift-left-testing/184404768|journal=Dr. Dobb's Journal|volume=26|number=9|pages=56, 62|via=}}</ref><ref>{{Cite web|url=http://collaboration.cmc.ec.gc.ca/science/rpn/biblio/ddj/Website/articles/DDJ/2001/0109/0109e/0109e.htm|archive-url=https://web.archive.org/web/20140810171940/http://collaboration.cmc.ec.gc.ca/science/rpn/biblio/ddj/Website/articles/DDJ/2001/0109/0109e/0109e.htm|url-status=dead|archive-date=2014-08-10|title=Sep01: Shift-Left Testing|date=2014-08-10|access-date=2019-09-06}}</ref>

== Harm due to late testing ==

Line 13:

== Types of shift-left testing ==

There are four basic ways to shift testing earlier in the life-cycle (that is, leftward on the classic [[V-model]]). These can be referred to as traditional shift-left testing,<ref>{{cite web|url=http://www.velocitypartners.net/blog/2014/01/28/agile-testing-the-agile-test-automation-pyramid/ |title=Agile Testing - The Agile Test Automation Pyramid |author=Velocity Partners | date=28 January 2014 |accessdateaccess-date=27 March 2015}}</ref> incremental shift-left testing, Agile/DevOps shift-left testing,<ref>{{cite web|url=http://www.slideshare.net/Urbancode/shift-left |title=Shift Left: Approaches and Practices |author=Paul Bahrs | date=6 November 2014 |accessdateaccess-date=27 March 2015}}</ref><ref>{{cite web|url=https://www.ibm.com/developerworks/community/blogs/invisiblethread/entry/enabling_devops_success_with_shift_left_continuous_testing?lang=en |title=Enabling DevOps Success with Shift Left Continuous Testing |author=Dibbe Edwards | date=18 September 2014 |accessdateaccess-date=27 March 2015}}</ref> and model-based shift-left testing.<ref>{{cite web|url=http://blog.sei.cmu.edu/post.cfm/using-v-models-testing-315 |title=Using V Models for Testing |author=Donald Firesmith | date=11 November 2013 |accessdateaccess-date=27 March 2015}}</ref>

=== Traditional shift-left testing ===

As illustrated in the following figure, traditional shift-left moves the emphasis of testing lower down (and therefore slightly to the left) on the right hand side of the classic V model. Instead of emphasizing acceptance and system level testing (e.g., [[GUI testing]] with record and playback tools<ref>{{cite web|url=https://msdn.microsoft.com/en-us/library/dd286714.aspx |title=Record and Playback Manual Tests |author=Microsoft | date= 2013 |accessdateaccess-date=27 March 2015}}</ref>), traditional shift-left concentrates on [[unit testing]] and [[integration testing]] (e.g., using [[API testing]] and modern test tools). The transition to traditional shift-left testing has largely been completed.{{By whom|date=April 2016}}

<gallery>

Traditional-Shift-Left.jpg|Traditional shift-left testing

Line 34:

=== Model-based shift-left testing ===

The previous forms all concentrated on testing earlier in the development cycle. However, they all test ''after'' software exists and seek to uncover only implementation defects. Model testing theory argues that 45% to 65% of defects are introduced before implementation, during requirements gathering, architecture, and design.<ref>{{cite web|url=http://www.iiste.org/Journals/index.php/CEIS/article/viewFile/3533/3581 |title=Quality Flaws: Issues and Challenges in Software Development |author1=P Mohan |author2=A Udaya Shankar |author3=K JayaSriDevi |name-list-style=amp | date=2012 |accessdateaccess-date=27 March 2015}}</ref>

Model-based testing moves testing to the left side of the Vs, by testing requirements, architecture, and design models. This shift begins testing almost immediately, instead of waiting a long time (traditional testing), medium time (incremental testing), or short time (Agile/DevOps) for software to become available to the right side of the Vs. This trend is just beginning.