The Skill of Agile development – Test Driven development

Introduction

Software development is a very challenging task, in which fault occurs commonly. In the old-fashioned development approaches, most errors and faults are found during build stage. These approach lead to different kind of problem being detected in later stages, often when the application is being used by the end user. This is the perspective for Test Driven Development (TDD). The Test Driven Development is a software development technique, a lot associated to agile methods.

Test Driven Development 

Test-driven development (TDD) is an evolutionary method to development having quick cycle of fulfilling testing, coding, and refactoring. When accumulating a feature, there can be repetition of these cycles, executing and refining the software in small development steps until there is no addition or deletion left. As per various researches carried out, result shows Test driven development substantially reduces the incidence of defect. When used properly, it also helps improve your design, documents your public interfaces, and guards against future errors.

The software development process with respect to Test Driven Development, also known as Red-Green-Refactor cycle, outlooks the repetition of running of the development steps.

First is to mark a unitary test that fails before writing any functional code, this turns out to be a Red phase; to write a functional code up until the unitary test is approved i.e. it turns to Green; during termination, if necessary, to restructure and reform the code, removing redundancies and refining its structure, assuring that all unitary tests are successful i.e. Refactor.

Test Driven Development also mentions the test automation, so there is always a built code which can run as part of regular process. Thus, guaranteeing that the addition of a new feature or restructuring the code doesn’t ruin features which exists already.

Benefits of Test driven Development:

• Maintainable, Flexible, Easily Extensible
  - As the testing in Test Driven development is incorporated into the development process at the most granular level, it is definite that every standalone piece of logic can be tested. At the end of the application development, there many test cases. When any change is made to the application, the existing test cases is run to see if the change has adversely impacted the application. This eliminates all roadblocks from keep informing legacy applications and making alterations within the current development.
• Clean Interface
  - As the test is written first by the programmers, the APIs they build are written from an API-user viewpoint. Thus, these APIs are too easy to use than those written by programmers more concerned with the internal workings of their packages.
• Unparalleled Test Coverage & Streamlined Codebase
  - In Test Driven Development, code is written after writing a test. This marks to unprecedented test coverage. Additionally, the refactoring process ensures written code is as reasonable as possible, restructuring the code base. This eases maintenance and helps improve scope.
• Refactoring Encourages Improvements
  - The refactoring process central to Test Driven Development confirms that developers constantly strengthens of the code base. This prevents applications from growing dated and monolithic

Conclusion: 

As the testing modules are put together into continuous integration development model, software development organizations using a Test Driven Development approach can easily make variations to their applications without panic of ‘breaking’ the application and restricting their daily operations.

References :

http://www.mindsource.pt/en/content/test-driven-development-agile-methodology
http://www.base36.com/2012/07/benefits-of-test-driven-development/