Behavior Driven Development is a fantastic way to avoid a situation we commonly encounter in the cross-team software development process. Very often developers and business professionals are dissatisfied due to the large amount of extra work done and the amount of wasted time and resources.

In general, the most common problem we find is the lack of communication between both parties involved. The developers don´t understand what the merchant asks for and vice versa; the clients do not feel that the developers can understand what they ask for.

Behavior Driven Development, or BDD, is another agile software development process that encourages collaboration between software developers, QA, project managers, and the business team.

In November 2009 in London, Dan North defined BDD as a second-generation, inside-out, push-based, diverse stakeholder, diverse scale, highly automated Agile methodology. It describes a cycle of interactions with very well defined outputs, resulting from the delivered work, with important tested software.

It allows the technical team and the business team to achieve their goals. In fact, it helps define the desired business lines, communicate what needs to be done by the developer and understand what technical challenges they may encounter.

Basically, with BDD the focus is on getting a good understanding of the behavior of the software you want to reach, communicating it to the stakeholders. So developers keep the focus on the reasons why the code is being created instead of focusing too much on the technical details. Now that we know a bit more about BDD, let's see how it differs from TDD.

Behavior Driven Development VS Test Driven Development
Many think that BDD and TDD are the same, but they are wrong. When we talk about TDD, we talk about an established process. Basically, automated unit tests are used to give developers direction on how to design the software.

I'd say the biggest difference is that behavior-driven development describes test cases in a natural language that non-programmers are capable of reading. To express a code´s purpose, developers combine their native language with the ubiquitous language of DDD (Domain Driven Design).

Instead of hardcoding functions, you tell the code exactly what you want it to do, using a style that is closer to how we write sentences. You get a clearer understanding of what the system should do from a developer and customer perspective, whereas TDD only gives the developer an idea of what the system should do.

That means that BDD allows developers and customers to work together on the requirements analysis that is contained in the system´s source code. Therefore, BDD becomes quite useful when it comes to communicating with all members of a cross-functional product team.

Instead of having tests that are only useful to engineers, you have one test that helps everyone. It improves collaboration between parties and allows developers to get a clearer scope of features that are required and the customer has a better idea of what will be delivered, with realistic estimates.

BDD directly influences software design, while TDD focuses on testing. So we can say that TDD focuses on the system implementation aspect while BDD, as the name suggests, focuses on the behavioral aspect. The priority is not how it will be implemented, but more about what the user will be able to do and what the user will be able to see.

Then, which is better? None. They must be used together!
Benefits of BDD or Behavior Driven Development
First of all, strong collaboration. With BDD, all parties involved have a great understanding of the project and can all have a role in communication and really have constructive discussions. BDD increases and improves collaboration.

It allows everyone involved in the project to easily participate in the product development cycle. And by using plain language, everyone can write behavioral scenarios.
Also, high visibility is an important advantage. By using a language that everyone understands, everyone gets great visibility into the progress of the project.

Another advantage is that software design follows business value. In fact, BDD places great importance on the business value and needs. By prioritizing the customer, based on the value it provides, developers can deliver better results because they have a strong understanding of how the customer thinks. By focusing on value, useless features are not created.