What problem does it solve? Testing code that calls external APIs like Stripe, Twilio, or SendGrid is slow, costly, and unreliable when it hits real services. This Skill builds drop-in mock clients with configurable failure modes so test suites run offline, in CI/CD pipelines, and against error scenarios that are hard to reproduce with live APIs. ## Core Features & Use Cases - Backend mock classes: Generates MockTwilioClient, MockStripeClient, MockSendGridClient, MockAzureSearchClient, MockSterlingClient, MockCertnClient, and MockPayPalClient under apps/utils/mocks/, each with a failure_mode parameter covering success, timeout, rate limit, card declines, bounces, and FCRA adverse-action flows. - Failure injection patterns: Provides pytest monkeypatch snippets that patch the exact import paths used by existing conftest fixtures, so new mocks extend rather than duplicate current test setup. - Frontend MSW handlers: Scaffolds Mock Service Worker handler files for auth, calendar, and payments endpoints once the frontend test scaffold exists. - Use Case: You need to verify your checkout flow handles a declined card. Invoke the Skill with the stripe service and card_declined mode, then assert your API returns the correct 400 response without touching Stripe. ## Quick Start Ask the AI to create mock layers for all external services in success mode so the test suite runs fully offline.
