# Shift-Left Testing - Wikipedia ![rw-book-cover](https://readwise-assets.s3.amazonaws.com/static/images/article4.6bc1851654a0.png) URL:: https://en.wikipedia.org/wiki/Shift-left_testing Author:: en.wikipedia.org ## Highlights > Shift-left testing is an approach to software testing and system testing in which testing is performed earlier in the lifecycle (i.e. moved left on the project timeline). It is the first half of the maxim "Test early and often." It was coined by Larry Smith in 2001. ([View Highlight](https://instapaper.com/read/1377523953/15501353)) > insufficient resources being allocated to testing ([View Highlight](https://instapaper.com/read/1377523953/15501414)) > Defects in requirements, architecture, and design remain undiscovered while significant effort is wasted implementing them. > Debugging (including identifying, localizing, fixing, and regression testing defects) becomes harder as more software is produced and integrated. > Encapsulation impedes white-box testing, reducing code coverage during testing.[citation needed] > There is less time to fix defects found by testing, thereby increasing the likelihood that they will be postponed until later increments or versions of the system. This creates a “bow wave” of technical debt that can sink projects if it grows too large. ([View Highlight](https://instapaper.com/read/1377523953/15501416)) > 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, incremental shift-left testing, Agile/DevOps shift-left testing, and model-based shift-left testing. ([View Highlight](https://instapaper.com/read/1377523953/15501418)) > Traditional shift-left testing ([View Highlight](https://instapaper.com/read/1377523953/15501419)) > Incremental shift-left testing ([View Highlight](https://instapaper.com/read/1377523953/15501422)) > Agile/DevOps shift-left testing ([View Highlight](https://instapaper.com/read/1377523953/15501427)) > Model-based shift-left testing ([View Highlight](https://instapaper.com/read/1377523953/15501435)) > 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.[citation needed] > 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. ([View Highlight](https://instapaper.com/read/1377523953/15501437)) --- Title: Shift-Left Testing - Wikipedia Author: en.wikipedia.org Tags: readwise, articles date: 2024-01-30 --- # Shift-Left Testing - Wikipedia ![rw-book-cover](https://readwise-assets.s3.amazonaws.com/static/images/article4.6bc1851654a0.png) URL:: https://en.wikipedia.org/wiki/Shift-left_testing Author:: en.wikipedia.org ## AI-Generated Summary None ## Highlights > Shift-left testing is an approach to software testing and system testing in which testing is performed earlier in the lifecycle (i.e. moved left on the project timeline). It is the first half of the maxim "Test early and often." It was coined by Larry Smith in 2001. ([View Highlight](https://instapaper.com/read/1377523953/15501353)) > insufficient resources being allocated to testing ([View Highlight](https://instapaper.com/read/1377523953/15501414)) > Defects in requirements, architecture, and design remain undiscovered while significant effort is wasted implementing them. > Debugging (including identifying, localizing, fixing, and regression testing defects) becomes harder as more software is produced and integrated. > Encapsulation impedes white-box testing, reducing code coverage during testing.[citation needed] > There is less time to fix defects found by testing, thereby increasing the likelihood that they will be postponed until later increments or versions of the system. This creates a “bow wave” of technical debt that can sink projects if it grows too large. ([View Highlight](https://instapaper.com/read/1377523953/15501416)) > 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, incremental shift-left testing, Agile/DevOps shift-left testing, and model-based shift-left testing. ([View Highlight](https://instapaper.com/read/1377523953/15501418)) > Traditional shift-left testing ([View Highlight](https://instapaper.com/read/1377523953/15501419)) > Incremental shift-left testing ([View Highlight](https://instapaper.com/read/1377523953/15501422)) > Agile/DevOps shift-left testing ([View Highlight](https://instapaper.com/read/1377523953/15501427)) > Model-based shift-left testing ([View Highlight](https://instapaper.com/read/1377523953/15501435)) > 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.[citation needed] > 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. ([View Highlight](https://instapaper.com/read/1377523953/15501437))