# SPDX-License-Identifier: Apache-2.0

import pytest

from vllm.core.scheduler import Scheduler
from vllm.engine.arg_utils import EngineArgs
from vllm.engine.llm_engine import LLMEngine
from vllm.sampling_params import SamplingParams
from vllm.v1.core.scheduler import Scheduler as V1Scheduler
from vllm.v1.engine.llm_engine import LLMEngine as V1LLMEngine


class DummyV0Scheduler(Scheduler):

    def schedule(self):
        raise Exception("Exception raised by DummyV0Scheduler")


class DummyV1Scheduler(V1Scheduler):

    def schedule(self):
        raise Exception("Exception raised by DummyV1Scheduler")


def test_scheduler_plugins_v0(monkeypatch):
    monkeypatch.setenv("VLLM_USE_V1", "0")
    with pytest.raises(Exception) as exception_info:

        engine_args = EngineArgs(
            model="facebook/opt-125m",
            enforce_eager=True,  # reduce test time
            scheduler_cls=DummyV0Scheduler,
        )

        engine = LLMEngine.from_engine_args(engine_args=engine_args)

        sampling_params = SamplingParams(max_tokens=1)
        engine.add_request("0", "foo", sampling_params)
        engine.step()

    assert str(exception_info.value) == "Exception raised by DummyV0Scheduler"


def test_scheduler_plugins_v1(monkeypatch):
    monkeypatch.setenv("VLLM_USE_V1", "1")
    # Explicitly turn off engine multiprocessing so that the scheduler runs in
    # this process
    monkeypatch.setenv("VLLM_ENABLE_V1_MULTIPROCESSING", "0")

    with pytest.raises(Exception) as exception_info:

        engine_args = EngineArgs(
            model="facebook/opt-125m",
            enforce_eager=True,  # reduce test time
            scheduler_cls=DummyV1Scheduler,
        )

        engine = V1LLMEngine.from_engine_args(engine_args=engine_args)

        sampling_params = SamplingParams(max_tokens=1)
        engine.add_request("0", "foo", sampling_params)
        engine.step()

    assert str(exception_info.value) == "Exception raised by DummyV1Scheduler"
