When deciding whether to use an external package like http in tests or to mock HTTP requests yourself, several factors come into play:
- Control and Predictability: Using your own mock API allows you to control the responses, making your tests predictable and reliable. External calls can introduce variability and dependencies on network conditions, server availability, and data changes.
- Speed: Mocking HTTP requests internally is faster. Real HTTP requests can slow down tests due to network latency.
- Isolation: Unit tests should isolate the code being tested. Mocking HTTP calls ensures that you’re testing only your code, not the external package or the server.
- Error Simulation: Mocks allow you to easily simulate various scenarios like timeouts, server errors, and different response formats, which can be harder to achieve with real HTTP calls.
- Version Control: While real HTTP tests can reveal bugs due to changes in external packages, it’s generally better to handle such issues with integration tests rather than unit tests.
Alternative Approach: Mock Server for Real HTTP Requests
Creating a mock server that the http package communicates with can be a middle ground. This approach ensures you are using the real http package while controlling the responses, but it adds complexity to the test setup.
Summary
- Mocking HTTP requests: Faster, more predictable, isolates the unit of code being tested.
- Real HTTP requests: Slower, less control, introduces external dependencies.
Choose based on the needs of your testing strategy, balancing between reliability, speed, and coverage.