Sharing State Between Steps in Cucumber - Tutorial

In Cucumber scenarios, there are often cases where you need to share state and data between different steps. This can be challenging since each step runs in isolation. However, Cucumber provides techniques to achieve state sharing and make scenarios more concise and organized. In this tutorial, you will learn how to share state between steps in Cucumber using scenario context and dependency injection.

Sharing State with Scenario Context

Scenario context is a built-in feature in Cucumber that allows you to share state between steps within the same scenario. The context object is created when the scenario starts and is accessible throughout the entire scenario execution.

Example:

    
public class SharingStateSteps {
  private int number;
  private int result;

@Given("I have entered {int} into the calculator")
public void enterNumber(int num) {
number = num;
}

@When("I press the add button")
public void pressAddButton() {
result = Calculator.add(number);
}

@Then("the result should be {int} on the screen")
public void checkResult(int expectedResult) {
assertEquals(expectedResult, result);
}
}

Sharing State with Dependency Injection

Dependency injection is another approach to share state between steps in Cucumber. It allows you to pass objects directly into the step definitions using constructors or setter methods.

Example:

    
public class SharingStateSteps {
  private Calculator calculator;
  private int number;
  private int result;

public SharingStateSteps(Calculator calculator) {
this.calculator = calculator;
}

@Given("I have entered {int} into the calculator")
public void enterNumber(int num) {
number = num;
}

@When("I press the add button")
public void pressAddButton() {
result = calculator.add(number);
}

@Then("the result should be {int} on the screen")
public void checkResult(int expectedResult) {
assertEquals(expectedResult, result);
}
}

Common Mistakes with Sharing State

• Not initializing the shared state properly, leading to unexpected results.
• Sharing sensitive or confidential data between steps, compromising security.
• Overusing shared state, making scenarios harder to understand and maintain.

Frequently Asked Questions (FAQs)

1. Q: Can I share state between scenarios?
   A: No, state sharing is limited to within a single scenario. Each scenario runs in isolation and cannot access state from other scenarios.
2. Q: Is scenario context thread-safe?
   A: No, scenario context is not thread-safe. Each scenario runs in its own thread, and concurrent access to scenario context can cause issues. Use dependency injection if thread safety is a concern.
3. Q: Can I share state between step definitions in different classes?
   A: Yes, you can share state between step definitions in different classes using dependency injection. Simply pass the shared object as an argument to the step definition constructors.
4. Q: What is the difference between scenario context and dependency injection for state sharing?
   A: Scenario context is specific to Cucumber and allows sharing state within a scenario. Dependency injection is a general programming concept and enables passing objects between classes, including step definitions.
5. Q: Can I share state between different scenarios using hooks?
   A: Yes, you can share state between different scenarios using hooks. Hooks provide before and after scenario execution points, where you can set up and tear down shared state.

Summary

Sharing state between steps in Cucumber can significantly improve the organization and reusability of your scenarios. Use scenario context for simple sharing within a single scenario, and employ dependency injection for more complex state sharing between different step definitions. Remember to avoid common mistakes and follow best practices to make your Cucumber scenarios more expressive and maintainable.