Role of Unit Testing in Agile Projects

What is Unit testing ?

Unit testing is a methodology where individual units of software,  associated  data,  and  usage procedures are tested  to determine  whether  they  operate  correctly.  The  unit  is usually  a small piece of code—for  example,  a single function.  The unit test is a short  function  that  tests the behavior  of the unit  that produces  a pass/fail  result.  This is achieved by performing the tested  function  on a known  value with  a single correct  result.

The main  purpose  of unit  testing  is to allow  developers  to identify as many problems  as possible at the development stage and  to do it in an automated, repeatable fashion  that  can be applied for every code change.

This makes developers directly responsible for producing working   code,  even  before  it  reaches  the  quality   assurance team.

What Does Unit Testing Have to Do with Agile Development?

I think the two are closely linked. In fact, I believe you can’t be truly agile without implementing  unit testing as an  integral  part  of the  development process.  Unit testing has several benefits that align closely with agile development principles.

The   central   benefit   of  unit   testing   is  that   it  produces working  code  faster  and  with  fewer  bugs.  The  ability  to  catch  bugs at the development stage reduces a huge amount of overhead  that  is otherwise  spent on releases that  are immediately  rejected  by QA due to basic functionalities being broken. Unit testing increases the chances of a new feature  working  correctly  upon  first delivery, as it becomes the developer’s responsibility to verify that he is delivering working code.

Another  reason  that  unit  tests  cut  down  on  development time is that  their  fine resolution allows  them  to pinpoint pre- cisely the  location  of a problem.  A failed unit  test can  direct the developer to the exact location  of the problem  in the code, allowing him to quickly resolve it. This minimizes or even eliminates  the time that  would  otherwise  be spent locating  the problem.

Unit testing may not be able to catch all bugs, but it is highly effective in catching regression bugs that are defects that break existing  functionality. These bugs hamper  progress  and  waste valuable  development and  QA resources  as code is sent back and forth between the two departments, delaying new versions of existing  products and  new product releases. Without unit  testing,  it is virtually  impossible  to  detect  bugs during the development phase.  This causes sprints  to become bogged down as developers need to spend more and more time fixing regression bugs in order to keep producing working software.  It becomes impossible  to maintain a steady and predictable software delivery schedule while also maintaining quality.  When a release date draws  near and the product is not working,  panic sets in, software  is released without enough  time to test it, and more bugs are introduced, creating a vicious cycle.

Code that  is not properly  maintained very quickly becomes legacy code that  developers  either refuse to change or insist on rewriting  themselves.  To keep code alive, you need to be able to change it and be confident that your changes won’t break anything.   Unit  testing  promotes   this  confidence.  Without it, you  end  up  either  refusing  to  change  older  code or  investing large amounts of time rewriting  it every so often.  In order  to respond  quickly  to change,  you need to be able to modify  all parts  of your  code  quickly  and  confidently. 

The Key Differences between Dev Testing and QA Testing

Although both Dev testing and QA testing help ensure the required level of quality of the software being developed, they differ in many ways. Here’s looking at the key differences between Dev testing and QA testing:

Unit Testing Tools and Techniques

Conclusion:

Unit testing is the earliest testing practice that focuses on the code. With this testing approach, small modules of the program are tested individually. This approach benefits the teams in many ways such as early bug detection, fixing the code before they become expensive to resolve in the SDLC. Hence, practicing unit testing is essential for businesses to ensure that the developed software is bug-free and quality is assured from the initial stage of SDLC.

Together  with the agile methodology, unit  testing  that  works  well within  your  programming environment is a crucial  necessity for managing  modern software  development.