test-strategylisted

# Test Strategy Tests are the executable spec. Optimize them for reading and for meaningful assertions, not for coverage numbers. ## What to test - Branch logic, boundaries, contracts, and error paths first. - Skip trivial pass-throughs, framework internals, and implementation details. - Test through the public surface, not private state or call order. ## TDD loop (new behavior) 1. Agree the seam where the test attaches before writing it. 2. Red: write one failing test for the next thin slice; watch it fail for the intended reason. 3. Green: write the least code that makes it pass. 4. Refactor as a separate step, with the test green as the safety net. Slice vertically (one thin path through every layer), not horizontally. One slice at a time. ## Bug-fix protocol 1. Write the regression test that reproduces the bug; it must fail for the reported reason. 2. Fix; the test goes green. 3. Run the surrounding suite so the fix did not move the bug elsewhere. ## Guardrails - DAMP over DRY: the failing output alone should say what broke. - Deterministic only: no real time, no real network, no order dependence, no logic inside a test. - Keep the pyramid: mostly unit, integration at real seams, few end-to-end. - If a test is impossible (non-deterministic or environment-bound), say so plainly rather than implying coverage. - Delegate mechanical scaffolding (boilerplate, fixtures, codemods) to a cheaper-tier subagent; keep the seam choice and the "is the behavior actually covere