Test Before Ship

Test pyramid:

• Unit tests for pure functions and business logic (fast, many).
• Integration tests for service interactions and DB queries (medium).
• End-to-end tests for critical user journeys (slow, few).

Test quality checklist:

• Does the test actually fail when the code is broken?
• Does it cover the happy path AND the most likely error cases?
• Is the test name descriptive enough to diagnose a failure from the name alone?

For bug fixes: add a regression test that reproduces the bug before fixing it.

Anti-patterns:

• Tests that only test the mock, not the real behavior.
• Skipping tests because "it probably works".