BDD vs.TDD Testing: What’s the Difference?

Code quality has reached new levels in the rapidly changing sphere of software development. Nowadays, we are observing two established testing methods that help teams ensure the necessary quality of the projects even before writing a single line of code. Those two popular methodologies are test-driven development and behavior-driven development, which form the basis of modern testing.

Each brings improvement to the developed software in its distinctive way. Therefore, in today’s article, we would like to offer you a closer look at those testing types, distinguish their features, and provide you with a clear understanding of how each of the testing methods might become beneficial for you and your end user.

What Is BDD?

BDD is a specific testing methodology that focuses on the equal contribution of both developers writing the code to the non-technical stakeholders, ensuring compliance with their vision and goals. It defines all development stages through clear specifications that help each team member track the project’s progress.

Another critical aspect of the BDD method is known as the “Given-When-Then” syntax, which defines specific scenarios by highlighting the conditions “given” initially. These conditions are later influenced by specific actions “when” and help to provide a particular outcome of the operation “then”. In the end, the BDD testing process greatly helps align the stakeholders’ goals with the technical realization of the project.

BDD Frameworks

The choice of framework can drastically change the overall BDD approach. Frameworks like Cucumber or SpecFlow provide you with functionality components that facilitate the implementation of the “Given-When-Then” logic. Talking about Cucumber, this platform can impress you with the availability of several programming languages and unique features that allow you to focus on greater collaboration between technical and non-technical team members.

On the other hand, SpecFlow focuses more on NET applications and provides convenient integrations with other frameworks. Ultimately, any chosen BDD framework can become an irreplaceable component of a successful lifecycle development process.

What Is TDD?

TDD is another major testing methodology. Its primary distinction is the focus on testing before the code development process. The importance of test-driven development is connected to the thorough emphasis on testing and implementing unit testing features that help achieve the necessary quality in the final product. Like the BDD, the test-driven approach has a logic named “Red-Green-Refactor”.

Firstly, the developer comes up with the feature they want to implement. During the “Red” stage, the feature fails purposely, followed by the “Green” stage, creating the minimal code base to enable the feature. During the final stage, called refactoring, the specialist restructures the code to ensure the best performance of the developed feature and the app’s overall robust and maintainable logic.

TDD Testing Frameworks

The good news is that TDD is tailored for different frameworks and works on various programming languages. Frameworks for TDD include well-known NUnit for NET. language or JUnit for even more popular Java. However, that is not all, since you can easily integrate TDD testing into JavaScript or Phyton and ensure the highest maintainability and performance for your projects despite your technical or business needs.

Difference Between BDD and TDD

We have briefly described both BDD and TDD in testing. Still, we would like to take our comparison to the next level. Therefore, below, we would like to present you with a more individual look at the similarities and differences of those testing methodologies.

Similarities

Let’s start with some principles common to behavior and test-driven developments:

• Testing before coding. Whether you choose BDD or TDD, both techniques establish testing before the start of the code development.

• Improvements in code quality. The earlier testing incorporation approach helps the team provide the best quality for the product and ensure maximum alignment with requirements.

Differences

The behavior of BDD and TDD might look almost similar at first glance, yet it isn’t. Therefore, in this section, we would like to explain what distinguishes those approaches:

• Different abstraction levels. While BDD can ensure a much higher level of abstraction due to the focus on the overall app’s performance, TDD only focuses on the separate components or units of the developed code.

• Collaboration. BDD is more suitable for companies where the team is looking for a full inclusion of all teams, starting from the non-technical members and finishing with engineers and QA specialists. On the other hand, TDD emphasizes a more technical or developer-centric approach using less involvement of the non-technical members.
• Testing fields. BDD employment is concerned with validating the whole system or product performance. Meanwhile, TDD can easily focus on testing the separate code blocks to ensure their maximal effectiveness.

Practical Applications

But what about some practical usage of the mentioned testing techniques? Let’s discuss some cases when the use of a particular technique might become more beneficial for the global project’s success:

When to Use BDD

• Presence of large teams. For example, if your company consists of various departments and includes many technical and non-technical employees, implementing the BDD should be your top priority. It will help to develop great internal connections between the multiple departments and enhance the effectiveness of the project.

• Complex requirements. BDD is your key to success when your team has to write a set of intricate testing cases. It helps structure the responsibilities between the team members and improve internal communication.

When to Use TDD

• Simpler products. If you are working on developing a simple application, using TDD will help you run the necessary tests without complex behavioral specifications.

• Compact teams. In cases when your team consists mainly of technical representatives, TDD should become your primary choice. It will allow you to easily communicate within the team without extensive collaboration.

Choosing the Proper Approach

An individual approach can help your team carefully evaluate your project and make a decision that will primarily benefit your future success. Here are some key factors that might help you choose the right option.

• Size & complexity of the project. Larger and more complex projects have more chances to benefit from BDD testing. In the meantime, it’s better to stick with the TDD for small and simple products.

• Team size and proficiency. Companies with a strong emphasis on technical developers usually prefer TDD. At the same time, the BDD is better for teams that listen to the opinions of non-technical specialists.

• Existing tools and processes. It’s also necessary to base your choice on the existing tools and established methods. Choose the option requiring minimal risk regarding implementing new technologies or approaches.

Hybrid Approaches

But let’s not forget about the possibility of successfully synchronizing both methodologies. It’s worth mentioning that a hybrid approach might become quite beneficial in multi-layered applications when you have to align with the stakeholders’ expectations and meticulously run tests regarding the separate program’s features. With a hybrid approach, you can receive successful internal communication and thorough testing that brings an impeccable product.

Best Practices

To successfully use BDD and TDD, it’s crucial to start with the stakeholders’ involvement regarding the definition of the requirement. Furthermore, it’s necessary to keep the documentation and internal communication transparent and open to maintain fruitful cooperation between the team. On top of that, do not forget about regular code refactoring and revisiting old approaches to find more profitable solutions.

Conclusion

Both BDD and TDD share focus on the testing before the actual code development. Still, these methodologies significantly differ in collaboration approaches and abstraction coverage, which makes the methodology’s choice essential for the project’s success. Therefore, if you are looking for tailored solutions that meet your business needs ideally, contact our team directly, and we will help you to test your product to perfection.