This skill sets up comprehensive testing suites using Cypress for both component and end-to-end testing. Component testing uses cy.mount() with framework-specific adapters for React, Vue, and Angular, configured through component.devServer in cypress.config.ts. E2E tests leverage cy.visit() for page navigation, cy.get() with data-cy attribute selectors for reliable element targeting, and cy.contains() for text-based lookups. Network stubbing uses cy.intercept() to mock API responses with fixture files loaded via cy.fixture(). The agent configures custom commands in cypress/support/commands.ts for reusable login flows, API seeding, and assertion helpers. Time travel debugging is enhanced through cy.screenshot() on failure and video recording configuration. The skill sets up Mochawesome reporter via cypress-mochawesome-reporter for HTML report generation with embedded screenshots. Environment-specific configurations use Cypress.env() with cypress.env.json files for different deployment targets. Retry logic uses retries configuration in cypress.config.ts with separate runMode and openMode settings. Includes GitHub Actions integration with cypress-io/github-action for CI pipeline execution.