Module 09 Summary

What this module established

TestClient runs the full request path in-process - routing, validation, dependencies, response models and error handling - with no server and no network. That covers most of what actually breaks.

Carry forward

• Reset shared state in fixtures. Tests depending on each other's leftovers fail in ways that point at the wrong test.
• Override the expensive dependency and clear it afterwards. Overrides are global to the app object.
• Assert allowed values, ranges, required fields and the absence of extras - the last one catches an internal field leaking.

Before moving on

Move on when your offline suite covers every declared error status and runs in seconds with no key.

Mark complete