End-to-end parity tests for the Stable Audio Open 1.0 pipeline + the Oobleck VAE component. They compare FastVideo against the published weights and the official Stability-AI/stable-audio-tools reference, so they're skipped in CI and run locally on a single GPU.

Setup

1. Hugging Face access

Stable Audio Open 1.0 is a gated repo. Accept the terms once at https://huggingface.co/stabilityai/stable-audio-open-1.0 and export your token in the shell:

export HF_TOKEN=hf_...
# any of HF_TOKEN / HUGGINGFACE_HUB_TOKEN / HF_API_KEY works

The tests skip cleanly with a helpful message if no token is set.

2. Optional inference dependencies

k_diffusion and friends are not part of FastVideo's base install. One-shot:

uv pip install k_diffusion einops_exts alias_free_torch torchsde

3. Clone the upstream reference repo

The pipeline-level parity tests (test_stable_audio_pipeline_parity.py, test_stable_audio_a2a_parity.py) and the VAE-component parity tests (test_oobleck_vae_parity.py, test_oobleck_vae_official_parity.py) import directly from stable_audio_tools. Clone it under the repo root and uv pip install editable, then add it to .gitignore:

cd <FastVideo repo root>
git clone --depth 1 https://github.com/Stability-AI/stable-audio-tools.git
uv pip install --no-deps -e ./stable-audio-tools
echo "/stable-audio-tools/" >> .git/info/exclude   # personal ignore

The smoke test and the inpainting self-consistency test do not need the upstream clone.

4. (Optional) Pre-warm the model cache

The first parity-test run downloads the full Stable Audio Open 1.0 checkpoint (~3 GB). To avoid the download blocking your first test run, fetch it ahead of time:

python -c "from huggingface_hub import snapshot_download; \
           snapshot_download('stabilityai/stable-audio-open-1.0')"

Running the tests

All Stable Audio tests in one shot (~80 s on a single B200):

pytest tests/local_tests/stable_audio/test_stable_audio_pipeline_smoke.py \
       tests/local_tests/stable_audio/test_stable_audio_pipeline_parity.py \
       tests/local_tests/stable_audio/test_stable_audio_a2a_parity.py \
       tests/local_tests/stable_audio/test_stable_audio_inpaint_parity.py \
       tests/local_tests/stable_audio/test_oobleck_vae_parity.py \
       tests/local_tests/stable_audio/test_oobleck_vae_official_parity.py \
       -v -s

Or, to run the entire family:

pytest tests/local_tests/stable_audio/ -v -s

Add -s to print the per-test diff numbers (shape / abs_mean / max diff / drift / RMS ratios).

What each test covers

Test	Compares against	Notes
`test_stable_audio_pipeline_smoke.py`	— (no GPU)	Imports + registry + preset wiring. CPU-only.
`test_stable_audio_pipeline_parity.py`	`stable_audio_tools.inference.generate_diffusion_cond`	T2A end-to-end. Drift bound: < 1% / 0.05 element-wise.
`test_stable_audio_a2a_parity.py`	`generate_diffusion_cond(init_audio=...)`	Audio-to-audio variation. Drift bound: < 2% / 0.05 mean.
`test_stable_audio_inpaint_parity.py`	self-consistency	RePaint blending — kept-region RMS ratio in [0.5, 2.0], unkept region non-silent + bounded. SA Open 1.0 isn't inpaint-trained so there's no upstream reference to compare against.
`test_oobleck_vae_parity.py`	`stable_audio_tools.models.AudioAutoencoder` (real weights)	Decode + encode + round-trip; should be bit-identical (fp32, diff = 0).
`test_oobleck_vae_official_parity.py`	`OobleckEncoder` / `OobleckDecoder` (random init)	Architectural parity — verifies the FastVideo port matches upstream's structure. Bit-identical (diff = 0).

Reproducing a single test

Each test file is independent. Run one:

pytest tests/local_tests/stable_audio/test_stable_audio_a2a_parity.py -v -s

Expected output (approximate, on a B200, fp32, default seed = 0):

off shape=(1, 2, 66150) abs_mean=0.181810
fv  shape=(1, 2, 66150) abs_mean=0.180913
diff max=0.030 mean=0.003 median=0.002  abs_mean rel drift=0.49%
PASSED

Troubleshooting

All tests skip with "gated repo" reason. Check echo $HF_TOKEN and that you've accepted the model terms at https://huggingface.co/stabilityai/stable-audio-open-1.0.
ModuleNotFoundError: stable_audio_tools / k_diffusion. Re-run the setup steps; the parity tests skip cleanly if these aren't importable but only after detecting both, so a partial install can produce an unhelpful error mid-test.
A2A or inpaint test passes individually but fails in a batch run. The deterministic-math toggles (TF32 / cuDNN benchmark off) are set in StableAudioPipeline.load_modules. If a test earlier in the batch flipped them on, drift can spike — re-run the failing test alone to confirm.
Wall-clock blew up past 5 min. First call downloads the checkpoint and the T5-base weights (~4 GB total) — see the pre-warm step above.

Adding new parity tests for this family

Use any of the existing test_stable_audio_* files as a template — the HF-token detection (_hf_token / _can_access / _setup_hf_env) and the loader for the official model (_load_official) are duplicated across the parity-test files; copy them as a starting point and call out the comparison reference (upstream class + invocation) in the file docstring.