Friday, March 4, 2011

Behavior Driven Development

Dan North in his blog about Behavior Driven Development write the following:

" If we could develop a consistent vocabulary for analysts, testers, developers, and the business, then we would be well on the way to eliminating some of the ambiguity and miscommunication that occur when technical people talk to business people."
He describes BDD as follows:

"BDD is a second-generation, outside-in, pull-based, multiple-stakeholder, multiple-scale, high-automation, agile methodology. It describes a cycle of interactions with well-defined outputs, resulting in the delivery of working, tested software that matters."

The practices of BDD include:

  • Establishing the goals of different stakeholders required for a vision to be implemented
  • Drawing out features which will achieve those goals using feature injection
  • Involving stakeholders in the implementation process through outside-in software development
  • Using examples to describe the behavior of the application, or of units of code
  • Automating those examples to provide quick feedback and regression testing
  • Using 'should' when describing the behavior of software to help clarify responsibility and allow the software's functionality to be questioned
  • Using 'ensure' when describing responsibilities of software to differentiate outcomes in the scope of the code in question from side-effects of other elements of code.
  • Using mocks to stand-in for collaborating modules of code which have not yet been written