Are mocks or stubs used in API testing to isolate components?

Yes, during API testing, mocks and stubs are often used to isolate components. This allows testing individual parts of the system independently of external dependencies.

• Stubs are simple placeholders that return fixed data, simulating the behavior of a real component.
• Mocks are more complex objects that not only simulate behavior but also verify how they were called (e.g., with what parameters and how many times).

Example: when testing an API service that interacts with a database, the real database call can be replaced with a mock to test data processing logic without needing a real database connection.

This increases the reliability and speed of tests, and also helps identify logical errors without external factors influencing the results.