Aeo Tdd Workflow

Use when practicing TDD: writing the failing test first, making it pass with the minimum code, refactoring under green, choosing between unit, integration, and end-to-end tests, or deciding how to build fixtures (inline, factory functions, shared pytest fixtures). Covers the red-green-refactor cycle with the mistakes at each phase, test-first case ordering, the transformation priority premise, Arrange-Act-Assert, fixture strategies, and test isolation, with Python examples.

Use when designing a test strategy or reviewing QA practice: deciding the test pyramid split between unit, integration, and end-to-end tests, fixing test anti-patterns (the liar, the giant, the mockery, the inspector, the flaky test), writing parameterized or table-driven tests, adding property-based tests, reading mutation testing results, or interpreting code coverage numbers. Python and pytest examples throughout.