Testing Fundamentals
Automated tests prevent regressions, document behaviour, and let you refactor safely. The test pyramid (unit, integration, end-to-end) tells you where to put most of your effort — at this level, mainly unit tests and basic integration tests, with end-to-end testing only introduced conceptually. Writing tests with a test-first mindset, structured as arrange-act-assert, and reading a coverage report as a useful signal rather than a guarantee, are the habits that make testing worth the time it costs.
Starting Points
Key Points
- You write unit tests that cover happy paths, error paths (invalid input, failures), and basic exception paths.
- You structure tests clearly (e.g. arrange-act-assert) and use meaningful test names that describe behaviour, not implementation.
- You use your stack's standard testing framework to run tests locally, interpret the output, and fix failing tests.
- You implement at least one basic integration test that exercises multiple components together (e.g. controller + service, or UI component + mocked API).
- You explain the difference between unit, integration, and end-to-end tests, and can justify when a unit test is enough vs. when you need an integration test.
- You interpret a simple code coverage report and can explain its limitations — high coverage doesn't automatically mean good tests.