Mocking & Stubbing

Summary

Replacing real dependencies (a database call, an external API, the current time) with fake, controllable versions in your tests — so tests are fast, deterministic and isolated.

• 1Mock a third-party API call in a test so it doesn't make a real network request.
• 2Stub a database call to return known test data without hitting a real database.
• 3Learn the difference between a mock (verifies it was called) and a stub (just returns data).