Working with Steps and Step Definitions in Cucumber - Tutorial

In Cucumber, steps and step definitions play a crucial role in writing BDD (Behavior-Driven Development) test scenarios. They bridge the gap between the plain-text Gherkin feature files and the actual test automation code. In this tutorial, we will explore how to work with steps and step definitions, providing examples and highlighting common mistakes to avoid for better BDD test automation.

Introduction to Steps and Step Definitions

Steps: Steps are the individual statements or actions written in the Gherkin language within a scenario. They describe the behavior of the application from the user's perspective and are written in a human-readable format.

Step Definitions: Step definitions are the automation code that maps the steps written in Gherkin to the actual implementation of the test. Each step in a scenario should have a corresponding step definition in the test automation code.

Example of Steps and Step Definitions

Consider a simple scenario where we want to test the addition of two numbers using Cucumber:


    Feature: Addition

    Scenario: Add two numbers

    Given the first number is 10

    And the second number is 20

    When I add the numbers

    Then the result should be 30

In the above scenario, the steps "Given the first number is 10," "And the second number is 20," "When I add the numbers," and "Then the result should be 30" need corresponding step definitions in the automation code.


    Given("the first number is {int}", (Integer number) -> {

      // Code to set the first number

    });

    Given("the second number is {int}", (Integer number) -> {

      // Code to set the second number

    });

    When("I add the numbers", () -> {

      // Code to perform addition

    });

    Then("the result should be {int}", (Integer result) -> {

      // Code to verify the result

    });

Steps to Work with Steps and Step Definitions

Follow these steps to effectively work with steps and step definitions in Cucumber:

Write Gherkin Steps: Define the steps for your scenario in the feature file using the Gherkin language.
Create Step Definitions: Implement step definitions in the test automation code to map each Gherkin step to its corresponding action or verification.
Use Regular Expressions: Use regular expressions to match dynamic data in step definitions.
Parameterize Steps: Utilize parameters in step definitions to make scenarios data-driven and reusable.
Keep Steps Atomic: Avoid combining multiple actions within a single step. Keep the steps atomic for better readability and maintainability.

Common Mistakes with Steps and Step Definitions

Using ambiguous step definitions that can lead to unintended matches.
Skipping proper parameterization, leading to less reusable and harder to maintain step definitions.
Creating step definitions that are too specific to the UI or implementation details, making them fragile.
Not following a consistent naming convention for step definitions, resulting in confusion and readability issues.
Writing lengthy and complicated step definitions that make it challenging to understand the scenario's purpose.

Frequently Asked Questions (FAQs)

Q: Can I reuse step definitions across different feature files?
A: Yes, step definitions can be reused across different feature files, making it easier to maintain and organize test automation code.
Q: How do I handle asynchronous operations in step definitions?
A: You can use Cucumber's built-in mechanisms like waiting strategies or custom synchronization methods to handle asynchronous operations.
Q: Can I use the same step for different scenarios with different parameter types?
A: Yes, you can use regular expressions with parameter capture groups to handle different parameter types in the same step definition.
Q: Should I create separate step definitions for Given, When, and Then steps?
A: While Cucumber does not enforce this, it is a good practice to separate step definitions based on the Gherkin keywords for better readability and maintainability.
Q: How do I debug step definitions?
A: You can use debugging tools like breakpoints or logging statements in your step definitions to inspect the behavior during test execution.

Summary

Steps and step definitions are the backbone of BDD test scenarios in Cucumber. By writing clear and reusable steps and mapping them to well-structured step definitions, you can create effective and maintainable test automation scripts. Following best practices and avoiding common mistakes will ensure that your BDD scenarios are concise, readable, and valuable for the entire team.