Debugging E2E Tests

1. Introduction

Debugging end-to-end (E2E) tests is an essential skill for developers and testers working with frameworks like Cypress and Playwright. This lesson will cover key concepts, common errors, a systematic debugging process, and best practices to help you effectively troubleshoot your E2E tests.

2. Key Concepts

2.1 What are E2E Tests?

E2E tests validate the entire application flow from start to finish, simulating real user interactions. They are crucial for ensuring that all components function together as expected.

2.2 Importance of Debugging

Debugging allows you to identify and fix issues in your tests, ensuring they provide reliable feedback on your application’s functionality.

3. Common Errors

• Flaky tests due to timing issues.
• Incorrect selectors causing tests to fail.
• Network issues leading to unexpected behavior.
• Environment configuration problems.

4. Debugging Process

4.1 Step-by-Step Debugging Flowchart

graph TD;
    A[Start Debugging] --> B{Is the test failing?};
    B -- Yes --> C{Check test logs};
    B -- No --> D[End];
    C --> E{Identify error type};
    E -- Flaky --> F[Add wait conditions];
    E -- Selector --> G[Update selector];
    E -- Network --> H[Check network status];
    E -- Config --> I[Verify configuration];
    F --> J[Test again];
    G --> J;
    H --> J;
    I --> J;
    J --> B;
        

4.2 Debugging Techniques

• Use Debugging Tools:

                cy.debug(); // Cypress: Pauses the test and opens the debugger
                await page.pause(); // Playwright: Pauses the test execution
            

• Console Logging:

                console.log('Debug Info:', variable);
            

• Run Tests in Isolation:

                npm run test -- --spec path/to/test.spec.js
            

5. Best Practices

• Keep tests small and focused.
• Use descriptive names for tests and selectors.
• Implement retries for flaky tests.
• Regularly review and refactor test code.

6. FAQ