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vllm-omni/tests/diffusion/models/ltx2/test_ltx2_transformer.py
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2026-08-14 00:13:14 +08:00

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Python

# SPDX-License-Identifier: Apache-2.0
# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
from types import SimpleNamespace
import pytest
import torch
from torch import nn
from vllm_omni.diffusion.attention.backends.abstract import AttentionMetadata
from vllm_omni.diffusion.cache.cachedit import CacheDiTAdapterConfig
from vllm_omni.diffusion.models.ltx2.ltx2_transformer import (
LTX2AudioVideoAttnProcessor,
LTX2VideoTransformer3DModel,
_LTX2ParallelAttention,
_make_rms_norm,
)
pytestmark = [pytest.mark.core_model, pytest.mark.diffusion, pytest.mark.cpu]
def test_ltx_rms_norm_no_affine_matches_official_torch_module():
norm = _make_rms_norm(8, eps=1e-6, elementwise_affine=False)
assert "weight" not in dict(norm.named_parameters())
assert norm.weight is None
assert "weight" not in dict(norm.named_buffers())
assert "weight" not in norm.state_dict()
def test_ltx_rms_norm_affine_weight_remains_parameter():
norm = _make_rms_norm(8, eps=1e-6, elementwise_affine=True)
assert isinstance(dict(norm.named_parameters())["weight"], nn.Parameter)
assert "weight" not in dict(norm.named_buffers())
assert "weight" in norm.state_dict()
def test_ltx_transformer_has_separate_cfg_cache_dit_config():
adapter_config = getattr(LTX2VideoTransformer3DModel, "_cache_dit_adapter_config")
assert isinstance(adapter_config, CacheDiTAdapterConfig)
assert adapter_config.has_separate_cfg
def test_ltx_transformer_exposes_hsdp_shard_conditions_for_blocks():
model = object.__new__(LTX2VideoTransformer3DModel)
nn.Module.__init__(model)
model.transformer_blocks = nn.ModuleList([nn.Linear(4, 4) for _ in range(2)])
model.norm_out = nn.LayerNorm(4)
conditions = getattr(model, "_hsdp_shard_conditions", None)
assert conditions is not None
assert len(conditions) == 1
matched = []
for name, module in model.named_modules():
if any(condition(name, module) for condition in conditions):
matched.append(name)
assert matched == ["transformer_blocks.0", "transformer_blocks.1"]
@pytest.mark.parametrize("rope_type", ["interleaved", "split"])
def test_ltx_sp_plan_shards_video_and_audio_timesteps_together(rope_type):
root_plan = LTX2VideoTransformer3DModel._build_sp_plan(rope_type)[""]
video_timestep = root_plan["timestep"]
audio_timestep = root_plan["audio_timestep"]
assert video_timestep.split_dim == audio_timestep.split_dim == 1
assert video_timestep.expected_dims == audio_timestep.expected_dims == 2
assert not video_timestep.split_output
assert not audio_timestep.split_output
def test_ltx_sp_keeps_cross_attention_key_padding_mask(monkeypatch):
monkeypatch.setattr(LTX2AudioVideoAttnProcessor, "_is_sp_enabled", staticmethod(lambda: True))
processor = LTX2AudioVideoAttnProcessor()
hidden_states = torch.zeros(1, 3, 4)
encoder_hidden_states = torch.zeros(1, 4, 4)
key_padding_mask = torch.tensor([[True, True, True, False]])
actual = processor._prepare_attention_mask(
SimpleNamespace(),
hidden_states,
encoder_hidden_states,
key_padding_mask,
batch_size=1,
sequence_length=4,
)
torch.testing.assert_close(actual, key_padding_mask[:, None, None, :])
def _fake_ltx_parallel_attention():
calls = []
class Backend:
@staticmethod
def get_name():
return "FLASH_ATTN"
@staticmethod
def supports_attention_mask():
return True
def run(name):
def forward(query, _key, _value, _metadata):
calls.append(name)
return torch.zeros_like(query)
return forward
layer = object.__new__(_LTX2ParallelAttention)
nn.Module.__init__(layer)
layer.attn_backend = Backend
layer.attention = SimpleNamespace(forward=run("native"))
layer.sdpa_fallback = SimpleNamespace(forward=run("sdpa"))
layer.backend_pref = "FLASH_ATTN"
return layer, calls
@pytest.mark.parametrize(("query_length", "key_length"), [(4, 4), (3, 4)])
def test_ltx_masked_cross_attention_uses_sdpa(query_length, key_length):
layer, calls = _fake_ltx_parallel_attention()
query = torch.zeros(1, query_length, 2, 4, dtype=torch.bfloat16)
key = value = torch.zeros(1, key_length, 2, 4, dtype=torch.bfloat16)
key_padding_mask = torch.tensor([[True] * (key_length - 1) + [False]])
metadata = AttentionMetadata(attn_mask=key_padding_mask[:, None, None, :])
layer._run_local_attention(query, key, value, metadata)
assert calls == ["sdpa"]
def test_ltx_masked_self_attention_uses_sdpa():
layer, calls = _fake_ltx_parallel_attention()
query = key = value = torch.zeros(1, 4, 2, 4, dtype=torch.bfloat16)
key_padding_mask = torch.tensor([[True, True, True, False]])
metadata = AttentionMetadata(attn_mask=key_padding_mask[:, None, None, :])
layer._run_local_attention(query, key, value, metadata)
assert calls == ["sdpa"]
def test_ltx_unmasked_cross_attention_keeps_native_backend():
layer, calls = _fake_ltx_parallel_attention()
query = key = value = torch.zeros(1, 4, 2, 4, dtype=torch.bfloat16)
layer._run_local_attention(query, key, value, None)
assert calls == ["native"]