Julia López - Testing Integrations: The Good, the Bad, and the Ugly - Rails World 2024

Test third-party API integrations by avoiding live HTTP calls in test suites using tools like VCR and WebMock

VCR records HTTP interactions during tests and replays them in future runs, preventing the need for repeated live API calls

Common integration testing challenges include:

• Slow API calls affecting test suite performance
• Rate limiting from third-party services
• Network conditions and timeouts
• Authentication/OAuth token management
• Fluctuating test data

Best practices for testing integrations:

• Mock external gem dependencies
• Use fixtures and stubs for predictable test data
• Serialize responses as JSON
• Match requests on method, host and path
• Parallelize tests when possible

When using both VCR and WebMock:

• Configure them to work together properly
• Disable HTTP connections by default
• Only enable specific requests needed for tests
• Use cassette naming conventions based on test descriptions

Maintain visibility into HTTP requests/responses for debugging:

• Review actual API interactions
• Monitor request parameters and headers
• Validate response payloads
• Track API version changes

Consider developer experience:

• Document authentication setup
• Provide helper utilities
• Use readable test fixtures
• Make cassette recreation easy
• Keep CI builds reliable

Balance between realistic integration tests and fast, stable test suites through strategic use of mocking and recording tools