Testing

Why I Stopped Mocking `fetch` and Reached for MSW

The two-handler MSW setup I drop into every Vitest project. Pattern-matched URL routing, typed JSON responses, and per-test overrides without re-importing the server.

Freeze Time and Fast-Forward in Jest

The clock-control playbook I keep on a sticky note: freeze `Date.now`, advance pending timers without sleeping, and write tests for debounce/throttle helpers that actually finish in milliseconds.

The pytest Fixture Builder I Cannot Live Without

A four-stage tour of the fixture-builder pattern: a callable factory that mints test models with sensible defaults, layered overrides, deterministic IDs, and per-test isolation. The shape I paste into every conftest.py.

Testing Pyramid vs Trophy: Pick the Right Shape

Most teams ship the testing pyramid by accident. The trophy is what actually matches modern frontend work. Here is how to choose.

How I Stopped My Jest Snapshots From Churning

A serializer that strips dates, ids, and request hashes out of snapshot JSON so a fresh git clone does not nuke the snapshot diff. Drop into `snapshotSerializers` and forget.

Dependency Injection Without a Framework

DI is a pattern, not a framework. The plain-language version (pass things in instead of newing them inside) covers ninety percent of cases. The trade-off versus DI containers, and where each one breaks down.