# IMPLEMENTATION — vram-detect-cross-platform-tests

Parent: `runnable-test-suite` (see PARENT_SPEC.md).
SPEC: `tasks/runnable-test-suite/subtasks/vram-detect-cross-platform-tests/SPEC.md`.

## File touched

- `tests/test_vram_detect.py` — extended with 11 new test functions + helpers.
  No other file was modified.

## Test functions added (11)

| # | Function | What it verifies |
|---|----------|------------------|
| 1 | `test_detect_ram_linux` | `/proc/meminfo` parse → `(16_384_000, 8_192_000)` via `detect_ram()` with `platform.system()` patched to `Linux`. |
| 2 | `test_detect_ram_macos` | `sysctl -n hw.memsize` → `"34359738368"` → total_kb `33_554_432`, available == total. |
| 3 | `test_detect_ram_windows` | `wmic ComputerSystem` → `TotalPhysicalMemory=34359738368` → total_kb `33_554_432`. |
| 4 | `test_detect_gpu_vram_nvidia_linux` | `nvidia-smi` → `"24576\n"` → `(25_165_824, 25_165_824, 1)`. |
| 5 | `test_detect_gpu_vram_apple_silicon` | `system_profiler` Apple M2 snippet + `sysctl hw.memsize=17179869184` → total > 0, num >= 1. |
| 6 | `test_detect_gpu_vram_windows_wmic` | `wmic win32_VideoController` → `AdapterRAM=8589934592` → total_vram_kb `8_388_608`. |
| 7 | `test_lookup_model_context_unknown_returns_zero` | `_lookup_model_context("completely-unknown-model")` → `0`. |
| 8 | `test_lookup_model_context_prefix_match` | `deepseek-r1:7b` → `64_000`; `llama-3.1-8b-instruct` → `128_000`. |
| 9 | `test_detect_model_context_ollama_probe` | No config model; `ollama list` returns `llama-3.1-8b` → context `128_000`. |
| 10 | `test_run_command_windows_powershell_wrapper` | On Windows, `Get-CimInstance ...` is routed through `powershell -NoProfile -NoLogo -Command "..."`. |
| 11 | `test_detect_ram_linux_regression` (LOCKED) | Exact match `(32_768_000, 16_384_000)` for a 32GB `/proc/meminfo` fixture via `_detect_ram_linux()`. |

Counting parametrize cases: **11 new tests** (no parametrization used; each function
is a single case).

## Existing tests modified

None. All 9 pre-existing test functions (`test_lookup_model_context`,
`test_parse_token_value`, `test_extract_value`, `test_parse_config_model`,
`test_parse_config_model_skips_code_blocks`, `test_parse_vram_config_manual`,
`test_recommend_context_api_model`, `test_recommend_context_manual_mode`,
`test_extract_model_from_file_respects_10kb_limit`) were preserved byte-for-byte.
No diffs to existing code.

## Mocking strategy

Every external call is mocked via `monkeypatch.setattr` — no live subprocess,
`system_profiler`, `nvidia-smi`, or `wmic` invocation:

- `vram.platform.system` → lambda returning the target OS string.
- `vram.subprocess.run` → `_make_fake_run(responses)` mapping `cmd[0]` (or the
  joined PowerShell string) to a canned `_FakeResult(stdout, returncode=0)`.
- `vram.shutil.which` → lambda returning a truthy name (or `None` for non-ollama
  in the ollama probe test).
- `Path.exists` / `Path.read_text` → `_patch_meminfo` serves the fixture only
  for `/proc/meminfo` and falls through to the original for any other path
  (keeps `tmp_path` and pytest internals working during the test).
- `vram.Path.home` → `tmp_path` in the ollama probe test so the real
  `~/.automaton/config.md` is never consulted.

Module-level multiline string fixtures: `MEMINFO_LINUX_16GB`,
`MEMINFO_LINUX_32GB`, `APPLE_M2_PROFILER`, `WMIC_VIDEOCONTROLLER`,
`WMIC_COMPUTERSYSTEM`, `OLLAMA_LIST`.

## Acceptance criteria

| Criterion | Result |
|-----------|--------|
| `pytest tests/test_vram_detect.py -v` exits 0, all new tests pass | PASS — 20/20 (9 existing + 11 new) |
| `pytest tests/ -v` exits 0 | PASS — 235 passed, 0 errors |
| Streak: 10 consecutive clean `pytest tests/ -v` runs | PASS — `STREAK_COMPLETE attempt=1 clean=10/10` |
| No live subprocess against real hardware | PASS — every `subprocess.run` / `shutil.which` / `Path` I/O patched |
| Every new test < 500ms | PASS — entire file 0.01s; slowest 60 durations < 0.005s |
| No `pytest.mark.skip` | PASS — none used |
| No new deps | PASS — stdlib + pytest only |
| Did NOT touch `scripts/vram_detect.py` | CONFIRMED — only `tests/test_vram_detect.py` edited |

## Final pass counts

- Baseline (`tests/test_vram_detect.py`): 9 passed.
- After implementation (`tests/test_vram_detect.py`): 20 passed (+11).
- Full suite baseline: 224 passed.
- Full suite after: **235 passed** (+11), 0 errors, 0 skipped.

## Streak result

```
STREAK_COMPLETE attempt=1 clean=10/10
```

## STOP-and-report triggers hit

None. All 11 SPEC-required tests passed against subtask-2's `vram_detect.py`
without any signature mismatch. No edits to `scripts/vram_detect.py` were
required or made. The `ollama list` probe (SPEC test 9) is present in
`vram_detect.py:525-539` and works as specified.