Organizations across the globe are feeling the pressure to churn out error free products faster and reduce the time to market. This has led to the growth of new development methodologies that put testing in the heart of product development and foster a growing collaboration between testers and developers. Some of these methodologies have also driven an increased impetus on test automation. Behavior Driven Development or BDD is one such methodology followed in agile product development. BDD is often considered the extension of Test Driven Development. The focus of BDD is on identifying required behavior in the user story and writing acceptance tests based on them. BDD also aims to develop a common language to drive development so that the team members understand the critical behaviors expected of an application and realize what their actual deliverables are.

It has become imperative for the development team to understand the business goals a product is expected to achieve if they wish to deliver quality products within the shortest timeframe. BDD puts the customer at the heart of the development approach. This approach iterates these requirements, the business situation and the acceptance criteria in Gherkin Language. The Gherkin Language is domain and business driven and easy to understand. The BDD approach identifies the behaviors that contribute directly to business outcomes by describing them in a way that is accessible to developers, domain experts, and testers. BDD leans heavily on collaboration, as the features and requirements are written collaboratively by the Business Analysts, Quality Analysts and the developers, in the GWT i.e. ‘Given-When-Then’ scenarios. These ‘scenarios’ are then leveraged by the developers and testers for product development. One of the main advantages of using Behavior Driven Development is that it makes the conversation between developers and testers more organized and that this approach is written in plain language. However, since the scenarios are written in a natural language they have to be very well written in order to reduce maintenance woes which otherwise can become tedious and time-consuming. The focus of BDD is to ensure that the development vocabulary moves from being singularly ‘test based’ to ‘business based’.

Role of Test Automation in Behavior Driven Development

We believe that the role of testing and test automation is of primary importance to the success of any BDD initiative. Testers have to write tests that verify the behavior of the system or product being built. The test results generated are in the form of success stories of the features and hence are more readable by the non-technical user as well. For Behavior Driven Development to be successful it becomes essential to identify and verify only those behaviors that contribute directly to business outcomes.

Testers in the BDD environment have to identify what to test and what not to test, how much should be tested in one go and to understand why the test failed. It can be said that BDD rethinks the approach to Unit and Acceptance testing. The sense is that acceptance criteria should be defined in terms of ‘scenarios’ as expressed in the GWT format. Here ‘Given’ defines the preconditions or contextual steps used to define the test case, ‘When’ is the event or the steps that have been taken and ‘Then’ is the final outcome of the scenario. Much like Test Driven Development, BDD too advocates that tests should be written first and should describe the functionalities that can be matched to the requirements being tested. Given the breadth of the acceptance tests in BDD, test automation becomes a critical contributor to success.

Since Behavior Driven Development focuses on testing behavior instead of testing implementation it helps greatly when building detailed automated unit tests. Testers thus have to focus on writing test cases keeping the scenario rather than code implementation in mind. By doing so, even when the requirements change, the testers do not have to change the test, the inputs and outputs to accommodate it. This makes unit testing automation much faster, less tedious and more accurate.
Since test cases are derived directly from the feature file set ups and contain example sets, they make for easy implementation and do not demand extra information for the test data. The automated test suites validate the software in each build and also provide updated functional and technical documentation. This reduces development time and also helps in driving down maintenance costs.

Though Behavior Driven development has its sets of advantages, it can sometimes fall prey to oversimplifications. Testers and development teams thus need to understand that while failing a test is a guarantee that the product is not ready to go to market, passing a test also does not indicate that the product is ready for release. At the same time, this framework will only work successfully when there is close collaboration between development, testing and business teams, where each can be informed of the updates and the progress in a timely manner. It is only then, that cost overruns that stem from miscommunications can be avoided. Since the testing efforts are moved more towards automation and cover all business features and use cases, this framework ensures a high defect detection rate due to higher test coverage, faster changes, and timely releases.

Have you moved the BDD way in your development efforts? Do share what challenges you faced, and how did the effort pan out?