# Step 0: build-test-harness

## Sprint Contract

### Objective
Establish the C++ project skeleton, build system, test framework, and validation script integration required before solver code begins.

### Required Reading
- /AGENTS.md
- /PROGRESS.md
- /PLAN.md
- /docs/README.md
- /docs/HARNESS_ENGINEERING.md
- /docs/PRD.md
- /docs/ARCHITECTURE.md
- /docs/ADR.md
- /docs/VERIFICATION_PLAN.md

### Scope
- Choose the Phase 1 build/test path. CMake is recommended unless project constraints require another choice.
- Add a minimal C++17 project skeleton with one smoke-test target.
- Wire `scripts/validate_workspace.py` to run real configured checks.
- Document the build-system decision in ADR if it changes or becomes explicit.

### Allowed Files
- `CMakeLists.txt` or the selected build-system files
- `src/**`
- `include/**`
- `tests/**`
- `scripts/validate_workspace.py`
- `README.md`
- `docs/ADR.md`
- `PLAN.md`
- `PROGRESS.md`
- `phases/1-linear-static-mitc4/index.json`

### Explicit Non-Goals
- Do not implement solver, parser, MITC4, results, or reference-comparison behavior.
- Do not introduce MKL, TBB, or HDF5 APIs into solver core during this setup step.
- Do not mark readiness blockers R-004 through R-011 as solved unless this step actually resolves them.

### Tests To Write First
- A minimal C++ smoke test that fails before the test harness is connected and passes after the harness is wired.
- A validation-script test or self-check proving `python scripts/validate_workspace.py` reports the configured build/test command status.

### Reference Artifacts
- None. This step does not use `references/*.inp` or `references/*_displacements.csv`.

### Acceptance Commands
```bash
python scripts/validate_workspace.py
```

### Evaluator Checklist
- The project builds with C++17 or newer.
- The chosen test framework runs through the validation script.
- `scripts/validate_workspace.py` no longer reports that no checks are configured.
- The build-system decision is documented if new or changed.
- No solver behavior was implemented.

### Handoff Requirements
- Update `PROGRESS.md` with changed files, validation output, and any build-system caveats.
- Update `PLAN.md` only for changed future work or resolved blockers.
- Update the matching phase index entry: use `completed` with a one-line `summary`, or `blocked` with `blocked_reason`, or `error` with `error_message`.

## Verification
1. Run the acceptance command.
2. Confirm the smoke test is executed by the validation script.
3. Inspect the diff for accidental solver behavior or dependency leakage.

## Do Not
- Do not expand Phase 1 scope to make a build demo more impressive.
- Do not commit generated build artifacts.