test-driven-developmentlisted

# Test-Driven Development (TDD) Skill ## 1. Core Principle: Red-Green-Refactor Production code is only written in response to a failing test that defines its requirements or reproduces a defect. --- ## 2. Four-Phase TDD Protocol ### Phase 1: RED (Write the Failing Test) - Author a concise, focused unit test in `src/test/java/.../*Test.kt`. - Test names must clearly describe the scenario and expected outcome (e.g. `loginViewModel_invalidPassword_emitsValidationError()`). - Capture both happy paths and boundary/error cases. ### Phase 2: PROVE FAILURE (Empirical Verification) - Execute the targeted unit test task: ```bash python .agents/scripts/run_gradle_task.py :app:testDebugUnitTest --tests "com.package.FeatureTest.testName" ``` - Verify that the test fails **for the expected assertion reason** (not due to a compilation failure or configuration error). ### Phase 3: GREEN (Minimal Implementation) - Write the minimal amount of production code required to make the failing test pass. - Re-run the targeted test to verify `BUILD SUCCESSFUL` and test pass. ### Phase 4: REFACTOR & HARDEN - Improve code readability, remove duplication, and extract reusable helpers. - Ensure strict adherence to Shift-Left Quality Invariants: 1. Single-source `StateFlow` unidirectional data flow. 2. Zero inline FQCNs. 3. Zero synchronous I/O on `Dispatchers.Main`. 4. Proper Coroutine cancellation and dispatcher handling (`StandardTestDispatcher` with `advanceUntilIdle()`). --- ##