# Testing

The suite is layered by dependency and purpose:

```bash
# Fast shared-package tests
uv run pytest tests/unit

# Full CPU suite, including integration and parity tests
uv run pytest

# Required ROOT-GNN parity gate (must fail if DGL is unavailable)
GNN4COLLIDERS_REQUIRE_ROOT_GNN=1 uv run pytest

# Optional layers
uv run pytest -m distributed -v
uv run pytest -m onnx -v
uv run pytest -m gpu -v
GNN4COLLIDERS_ROOT_FIXTURE=/path/to/reduced.root uv run pytest -m real_data -v
```

On Apple Silicon macOS, `uv sync --dev --extra root-gnn` supports CPU
ROOT-GNN unit and integration testing. CUDA and the required ROOT-GNN parity
gate are validated on Linux x86_64 with the `root-gnn` extra installed.

## Hugging Face parity automation

The scientific parity gate runs natively on the Hugging Face Hub. A repository
webhook watches PR commit refs (`refs/pr/<number>`) and triggers a Hugging Face
Job. The Job downloads the exact commit SHA from the webhook, installs the
`root-gnn` extra, and runs the strict parity suite:

```bash
GNN4COLLIDERS_REQUIRE_ROOT_GNN=1 uv run pytest tests/parity -v
```

The Job prints a versioned JSON report containing the commit, deterministic
parity-fixture digest, tolerances, and pytest summary, then comments the compact
result on the PR. The implementation is in `validation/hf_parity_job.py`;
webhook and Job registration are deployment configuration and must provide an
`HF_TOKEN` secret. The registration helper is
`validation/register_hf_parity_webhook.py`; it takes an already-created Job ID
and a webhook secret. Discussion-only events are ignored because they do not
identify a commit to test.

The Job image must provide `uv` and the project CI extra. A source Job command
can be run with:

```bash
uv run --extra ci python -m validation.hf_parity_job
```

## Hugging Face parity automation

The scientific parity gate runs natively on the Hugging Face Hub. A repository
webhook watches PR commit refs (`refs/pr/<number>`) and triggers a Hugging Face
Job. The Job downloads the exact commit SHA from the webhook, installs the
`root-gnn` extra, and runs the strict parity suite:

```bash
GNN4COLLIDERS_REQUIRE_ROOT_GNN=1 uv run pytest tests/parity -v
```

The Job prints a versioned JSON report containing the commit, deterministic
parity-fixture digest, tolerances, and pytest summary, then comments the compact
result on the PR. The implementation is in `validation/hf_parity_job.py`;
webhook and Job registration are deployment configuration and must provide an
`HF_TOKEN` secret. Discussion-only events are ignored because they do not
identify a commit to test.

Unit tests use deterministic, small tensors and generated ROOT files. DGL,
ONNX, CUDA, distributed execution, and reduced real-data fixtures remain
optional layers. Tests should assert public contracts and scientific
invariants rather than private call sequences. New regression tests should
use `tmp_path`, explicit seeds, and justified numerical tolerances.

Release validation additionally builds a wheel and runs the CLI help command
in a clean environment; it is not part of the ordinary pytest suite.