vllm/tests/v1/e2e/test_cascade_attention.py
Cyrus Leung 1e4ecca1d0
[V0 Deprecation] Remove VLLM_USE_V1 from tests (#26341)
Signed-off-by: DarkLight1337 <tlleungac@connect.ust.hk>
2025-10-07 15:42:31 +00:00

38 lines
1.3 KiB
Python

# SPDX-License-Identifier: Apache-2.0
# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
import pytest
from vllm import LLM, SamplingParams
from ...utils import create_new_process_for_each_test
@create_new_process_for_each_test()
@pytest.mark.parametrize("attn_backend", ["FLASH_ATTN", "FLASHINFER"])
def test_cascade_attention(example_system_message, monkeypatch, attn_backend):
prompt = "\n<User>: Implement fibonacci sequence in Python.\n<Claude>:"
if attn_backend == "FLASHINFER":
pytest.skip(
"This test is failing with FlashInfer backend and "
"needs investigation. See issue #25679."
)
with monkeypatch.context() as m:
m.setenv("VLLM_ATTENTION_BACKEND", attn_backend)
llm = LLM(model="Qwen/Qwen2-1.5B-Instruct")
sampling_params = SamplingParams(temperature=0.0, max_tokens=100)
# No cascade attention.
single_prompt = [example_system_message + prompt]
responses = llm.generate(single_prompt, sampling_params)
ref_output = responses[0].outputs[0].text
# (Probably) Use cascade attention.
prompts = [example_system_message + prompt] * 64
responses = llm.generate(prompts, sampling_params)
for response in responses:
assert response.outputs[0].text == ref_output