Category: Hands-on / Engineering

The Context While unit tests prove individual modules work, integration testing ensures that these components work together in harmony. The POC project demonstrates this through foo_get_integration_test.rs (or foo_post_integration_test.rs), which validates the complete flow from the endpoint to the 3rd party API. The Problem A common mistake is thinking that if all unit tests pass, the…

The Context Modern applications frequently communicate with 3rd party APIs. In the provided POC, the foo_service.rs and integration tests interact with external URLs. Testing these interactions is critical, as data can change or fail when transferred across modules. The Problem Relying on a real 3rd party API during testing is a major anti-pattern. Real APIs…

The Context In the POC project, particularly in foo_service.rs, we often need to test the same logic against multiple inputs. Writing a separate test function for every single variation (happy path, unhappy path, edge cases) quickly becomes a maintenance nightmare. The Problem Standard Rust tests can lead to significant code duplication. If you have five…

The Context When building complex Rust applications, you quickly realize that testing a single “unit” is difficult if it is tightly coupled to other services. Unit testing aims to ensure each part of the software performs as intended in isolation. However, controllers and services often depend on traits that handle database access or external logic,…