10 Tips for Writing Effective BDD Scenarios
When rolling out BDD having a clear and concise scenario writing is a vital aspect of successful BDD adoption. This blog post will provide you with 10 tips to enhance your BDD scenario writing, making it easy to understand, maintainable, and efficient.
1. Collaborate and Derive Scenarios
Effective collaboration with all stakeholders, including both business and technical, is crucial for the successful implementation of BDD. Failing to prioritize this step at the outset can result in a lack of buy-in and ultimately hinder the realization of any potential benefits.
2. Single Responsibility
Each scenario should have one and only one responsibility, or purpose. Having scenarios with a single responsibility makes them easier to understand, maintain and test. It also makes it easier to trace the scenario to a specific requirement or acceptance criteria
3. Scenario should be independent
An independent scenario is self-contained, meaning it has all the information it needs to be executed and understood without relying on other scenarios. This makes the scenarios more flexible and easier to understand, maintain and test.
4. Declarative scenarios
Declarative scenarios outline the desired behavior and outcome of a system, rather than the specific steps and actions required to achieve it.
In contrast, imperative scenarios provide details on how the system should accomplish a specific task.
Using imperative scenarios for describing system behavior tends to make them more technical and any changes to the system, even without requirement changes, can result in the need to update the scenarios.
5. Scenario Outline
Scenario outline enables you to run the same scenario multiple times with different inputs, without having to write a new scenario for each set of inputs.
Using scenario outline would result in better test coverage, maintainability, reduction in the number of scenarios and better readability
6. Limit number of scenarios per feature
Having too many scenarios per feature can make it difficult to understand the overall behavior of the system and can also make it more difficult to maintain and test the scenarios.The ideal number of scenarios per feature will vary depending on the complexity of the feature and the size of the project. However, as a general guideline, it is recommended to keep the number of scenarios per feature to a minimum.
7. Limit number of steps in a scenario
When there are too many steps, it is likely to be a side-effect of an imperative scenario (check tip 4) or the scenario doesn’t follow single responsibility (check tip 2)
8. Reuse Steps
Reusing steps is highly recommended when possible, as it can help to make the scenarios more efficient and easier to understand. Steps written in natural language can be prone to variations, so it’s important to establish clear guidelines for writing steps and to use parameters for reuse.
9. Verify the outcome
Verifying the outcome of a scenario is essential. In technical terms, each scenario should include at least one assertion step to ensure that the desired behavior has been achieved. Without this step, the scenario serves little purpose.
10. Continuous Improvement
Regularly reviewing and improving your scenarios is crucial for the success of BDD. As you gain more experience and understanding of your domain through writing BDD scenarios, it is important to incorporate that knowledge back into the initial scenarios. Continuously refining and updating your scenarios will lead to better and more accurate descriptions of the desired system behavior.