Local-only parity, registry, and pipeline-smoke tests for the ltx2 FastVideo port. Most tests depend on a checked-out LTX-2/ directory at the repo root (FastVideo/LTX-2) and converted Diffusers weights; without those they will skip or fail. Skipped in CI; run locally on a single GPU.

Reference Assets

Field	Value
Model family	`ltx2`
Workload types	`T2V` (video + optional audio)
Official reference	`Lightricks/LTX-2` (local clone)
Local reference dir	`LTX-2/` (with `LTX-2/packages/ltx-core/src` on `sys.path`)
Official commit/version	`<TODO>`
HF weights	`Lightricks/LTX-2`, `FastVideo/LTX2-base`, `FastVideo/LTX2-Distilled-Diffusers`
HF revision	`<TODO>`
Local weights dir	`<TODO>` (env: `LTX2_DIFFUSERS_PATH`, `LTX2_FASTVIDEO_GEMMA_LOG`, etc.)
Source layout	`<TODO: diffusers / raw_official / mixed>`
Needs conversion	`<TODO>`

Use only the env-var name for tokens (e.g., HF_TOKEN). Never paste a token value.

Shared Environment Setup

Run from the FastVideo repo root in the same env used for FastVideo. See the add-model-prep skill for canonical clone + install commands.

# Clone the official reference under the FastVideo repo root.
git clone <official_repo_url> LTX-2
uv pip install --no-deps -e ./LTX-2

Do not change core dependency versions (torch, diffusers, transformers, flash-attn, triton, CUDA packages) without explicit approval.

Official Environment Status

dependency_changes: <TODO>
official_env_status: <TODO: imports_ok | private_deps_need_stubs | blocked>
private_dep_stubs: <TODO>
blocked_on: <TODO>

Tests in this directory

Run the whole family:

pytest tests/local_tests/ltx2/ -v -s

Component	Test	Concerns	Status
`text encoder` (Gemma)	`test_ltx2_gemma_encoder.py`	encoder + connector	`<TODO>`
`text encoder` (Gemma, full parity)	`test_ltx2_gemma_parity.py`	full Gemma parity vs official	`<TODO>`
`transformer/DiT`	`test_ltx2.py`	LTX2VideoConfig DiT parity	`<TODO>`
`transformer/DiT` (audio modality)	`test_ltx2_audio.py`	audio-conditioning DiT parity (imports helpers from `test_ltx2.py`)	`<TODO>`
`vae` (video)	`test_ltx2_vae.py`	LTX2VideoEncoder/Decoder parity	`<TODO>`
`vae` (video, official path)	`test_ltx2_vae_official.py`	LTX2VAEConfig + VAELoader path	`<TODO>`
`vae` (audio)	`test_ltx2_audio_vae.py`	audio encoder/decoder/vocoder parity	`<TODO>`
`pipeline` (smoke)	`test_ltx2_pipeline_smoke.py`	VideoGenerator end-to-end smoke	`<TODO>`
`registry`	`test_ltx2_registry.py`	sampling/pipeline registry resolution	`<TODO>`

Review Notes

Required before handoff: non-skip PASS for each component parity test, including reused components that own weights or numerical behavior.
Pipeline parity may start as a scaffold; final handoff requires non-skip PASS or an explicit blocker accepted via the escape-hatch process.