Debugging & Troubleshooting Interview Questions

Cypress provides several debugging tools: 1) Debug command (.debug()), 2) Chrome DevTools integration, 3) Command log in Test Runner, 4) Time travel feature, 5) Screenshots and videos, 6) Console logging, and 7) Error messages with detailed stack traces.

The .debug() command pauses test execution and opens Chrome DevTools. It can be chained to any Cypress command to inspect the state at that point. Example: cy.get('button').debug().click(). This allows inspection of elements and application state.

cy.log() adds messages to the Command Log in the Test Runner. It's useful for debugging by providing additional context during test execution. Example: cy.log('Clicking submit button'). Messages appear in the test runner's command log.

Cypress provides detailed error messages, screenshots on failure, video recordings, and stack traces. It automatically retries failed assertions and provides clear failure reasons in the Test Runner. Failed tests can be debugged using time travel.

Time travel debugging allows you to see the state of your application at each step of test execution. The Test Runner snapshots the DOM at each command, allowing you to hover over commands and see the application state at that point.

Network requests can be inspected using the Network tab in DevTools, cy.intercept() for request monitoring, and Test Runner's command log. You can view request/response details, headers, and timing information.

Common causes include: 1) Race conditions, 2) Improper waiting, 3) Network timing issues, 4) Animations, 5) State dependencies between tests, 6) Resource loading issues, and 7) Inconsistent test data. Understanding these helps in writing more reliable tests.

Timeouts can be configured globally in cypress.config.js or per-command using timeout option. Default timeouts can be overridden, and custom timeout messages can be provided. Example: cy.get('button', { timeout: 10000 }).

Screenshots and videos are automatically captured on test failure (configurable). They help in debugging by providing visual evidence of test execution and failure points. Videos show the entire test run, while screenshots capture specific failure moments.

Synchronization issues can be debugged using proper waiting strategies, .debug() command at key points, and reviewing command log timing. Understanding Cypress's automatic waiting and retry mechanism helps prevent sync issues.

Async operations can be debugged using cy.wait() for aliases, proper assertions for completion, and monitoring network requests. Understanding Cypress's command queue and automatic waiting helps with async debugging.

DOM issues can be debugged using .debug() to inspect elements, Chrome DevTools for DOM manipulation, and proper element selection strategies. Understanding element visibility, actionability, and state helps resolve DOM issues.

Cross-origin errors can be debugged by checking chromeWebSecurity configuration, proper proxy setup, and understanding same-origin policy limitations. Implement proper workarounds or configurations for cross-origin requests.

State management debugging involves using cy.window() to access application state, monitoring Redux/Vuex store changes, and proper state assertions. Implement state inspection and verification at key points.

Memory leaks can be debugged using Chrome DevTools Memory profiler, proper cleanup in afterEach hooks, and monitoring resource usage. Implement proper resource cleanup and memory management strategies.

Performance issues can be debugged using Chrome DevTools Performance tab, monitoring command execution times, and proper test optimization. Implement performance monitoring and optimization strategies.

Custom command debugging involves proper error handling, logging within commands, and understanding command composition. Implement proper debugging strategies within custom commands.

Plugin issues can be debugged by checking plugin configuration, monitoring plugin execution, and proper error handling. Implement proper plugin debugging and troubleshooting strategies.

Configuration issues can be debugged by reviewing cypress.config.js, environment variables, and plugin configurations. Implement proper configuration validation and verification strategies.

CI/CD issues can be debugged using proper logging, artifact preservation, and environment configuration. Implement proper CI/CD debugging and troubleshooting strategies.

Advanced logging involves custom log formats, structured logging, and integration with logging services. Implement comprehensive logging strategies for complex debugging scenarios.

Complex async debugging involves proper command sequencing, state tracking, and comprehensive error handling. Implement advanced async debugging strategies for complex workflows.

Race condition debugging involves proper timing analysis, state verification, and comprehensive event tracking. Implement advanced strategies for identifying and resolving race conditions.

Memory-intensive debugging involves proper resource monitoring, memory profiling, and optimization strategies. Implement advanced memory management and debugging techniques.

Custom debugging tools involve creating specialized debugging utilities, custom commands, and debugging interfaces. Implement advanced debugging tool development strategies.

Distributed system debugging involves coordinated logging, state synchronization, and comprehensive system monitoring. Implement advanced strategies for debugging distributed test scenarios.

Performance bottleneck debugging involves comprehensive performance profiling, optimization analysis, and performance monitoring. Implement advanced performance debugging strategies.

Security debugging involves security testing tools, vulnerability analysis, and security monitoring. Implement advanced security debugging and testing strategies.

Custom framework debugging involves framework-specific tools, custom debugging utilities, and comprehensive testing strategies. Implement advanced debugging approaches for custom frameworks.

Integration debugging involves system integration testing, component interaction analysis, and comprehensive integration monitoring. Implement advanced strategies for debugging integration scenarios.