Software development is not just about writing code. Testing code thoroughly to ensure it meets essential criteria and standards is one of the biggest challenges for developers. Testing methodologies like Test Driven Development and Behavioral Driven Development can be helpful.

TDD involves writing tests prior to developing code. Contrarily, BDD focuses on evaluating a system’s behavior. TDD, BDD and ATDD are all common strategies that can help developers overcome the challenge of predicting user requirements and creating simple tests.

Acceptance Test Driven Development (ATDD), a popular testing technique, can be used to ensure that code meets the expectations of the end user. Software development is impossible without testing practices. Writing tests and planning time are essential to ensuring that the development team understands user requirements and produces quality software.

These tools are also used to analyze automated tests. This blog will examine the benefits and define the comparison between Test-Driven Development vs. Behavior-Driven Development. These testing techniques help you choose which strategy to implement in your software development processes.

What is Test-Driven Development (TDD)?

The programming methodology known as Test-Driven Development (TDD) is carried out from the perspective of the developer. A QA engineer will begin by designing and writing tests for each small feature of the application.

This technique attempts to answer the simple question: Is this code valid? This practice has as its primary goal to only modify or create new code when tests fail. It results in less duplication of scripts. This technique is most popular in agile development environments. As part of the TDD development methodology, functional code is not implemented until automated test scripts have been written. 

Benefits of Test-Driven Development (TDD)

• TDD reduces the cost of development by dividing the development process into smaller pieces to make it easier to detect issues in the early stages.
• Focus on architecture and design: By writing tests before implementation, the development process is more seamless.
• TDD can improve code coverage: A well-designed TDD system can provide 100 percent code coverage.
• Code visibility: Smaller functionalities are tested with tests, which makes it easier to maintain and refactor the code.
• Documentation in detail: Because tests are written to verify micro-level functionality, documentation is a simple task.

The drawback of Test-Driven Development (TDD)

• Bugs that lead to faulty code. Tests may contain bugs, which can then result in faulty implementation. You can avoid this by choosing the right BDD framework and performing a detailed code review.
• Costly architectural mistakes: If generated test code does not match the desired architecture it can result in large losses.
• Slowness in development: Product development is slowed down by writing test cases before writing code. Framing test cases may also take a lot of time, as the actual implementation will not be available until later.
• Experience with TDD required: Previous experience is essential, as many teams make the mistake of failing to run tests on the Red Stage.

What is BDD

BDD or Business-Driven Development is an extension of Test-Driven Development. It is based on the TDD core ethos that puts the test in front. In this instance, the tests focus on the behavior and performance of the system. These behavioral predictions are used to develop different features or components within an application. BDD testing uses the Given-When Then approach.

If the user has entered valid credentials, then you can predict what will happen next. The user will complete the login by clicking the button and then display the message of successful validation.

BDD testing, as is evident in the process above, is conducted in an easy-to-understand language. This makes it easier for the entire team to comprehend feature behavior. 

Benefits of BDD

• Communication is improved within the team. To create a scenario, a representative of the client, the project owner, testers, and developers must work together. The goal of the product will be widely understood by the whole project team.
• Reduces quality control costs. BDD requires the automation of acceptance tests for all expected user scenarios.
• This allows for more accurate estimates of tasks. As the functionality and behavior are discussed prior to the start of development, you are less likely to need to change the architecture or add new features.

• Focuses on the user’s experience. Test-Driven Development vs. Behavior-Driven Development is in that it forces the development team to focus more on the desired behavior than the implementation of features.
• Documentation that is constantly updated. You are encouraged to update executable specifications when tests fail due to an incorrect specification. A detailed set of scenarios and tests will also help new team members to become familiar with the product. 

Drawbacks of BDD

• It takes more time than the traditional development process. It can be challenging to get all the participants involved in creating a situation together, especially if you have a large team. The time and effort required to maintain scenarios and tests is something that some projects may consider as an overhead.
• If at least one of three amigos are not available, the development will be slowed down. To create a shared product understanding, three teams must constantly collaborate Management, Testing, and Development. If there isn’t mutual understanding among the team members, BDD will slow down progress.
• It is less efficient for simple projects and small development teams. There’s no reason to have your team discuss scenarios if you only have a few developers and they communicate with the testers and project managers every day. Small teams can still benefit from creating tests prior to coding.
• It is important to implement the scenarios at the beginning of the project. It’s of little or no use to create and discuss scenarios in the middle stages of development. This will force you to rework parts of your project that are already completed. Retrofitting scenarios or tests to legacy code would be nearly impossible and make no sense.

Test-Driven Development vs. Behavior-Driven Development – Comparison 

We have compiled a comprehensive table of Test-Driven Development vs. Behavior-Driven Development that you must take into consideration. So let’s have a look: 

Test-Driven Development vs. Behavior-Driven Development – Key Difference

TDD and BDD have become very popular today. They are both important techniques for software development. They are not, however, applicable everywhere. Test-Driven Development vs. Behavior-Driven Development is also ineffective and expensive when they are used on projects that don’t require them. This list highlights the right process to use in the following scenarios. 

• One-Time Projects: Many of the projects can be considered “one-time”. In the future, you don’t need to maintain these projects for a long time. In such situations, TDD is not the best approach. TDD will increase the cost of the initial project, which can only be compensated if it is maintained over a long period. BDD would be a good option.
• Projects based solely on GUI: It is not recommended to start a project with TDD. The team can still use TDD, but with a thin layer and without focusing on hard tests.
• Scope of Project: TDD and BDD are incompatible with each other. The first is used to write the test code and the second focuses on system functionality. TDD is therefore better suited for projects that do not have behavioral elements, such as those that use third-party tools and APIs. BDD, on the other hand, takes into account behavioral aspects and is, therefore, best suited to projects that are rich in user actions, such as ecommerce websites.
• Team Familiarity: In some cases, your team may not be familiar with TDD which requires domain knowledge. You can train your team, which will cost more and increase project delivery time. Or you can just skip TDD. If you are able to work without TDD and still get the benefits of this post, then you should use BDD.
• Presence of an Existing System: BDD is more suitable when you’re working on an existing system. The behavioral cases are simple to write and understand. TDD becomes a complex task when dealing with such processes.

Conclusion

This blog will help you to see the bigger picture and determine which method is right for your software needs. You will need strong testing and QA skills, regardless of whether you implement behavior-driven development or test-driven development.

Understanding Test-Driven Development vs. Behavior-Driven Development can help Agile teams, as well as other stakeholders, improve their development processes by determining the best testing strategy to suit their needs. You can then choose a combination of both techniques, depending on your project’s nature and desired results, to increase test coverage.

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