vllm-omni/tests/entrypoints/openai_api/test_image_server.py

# SPDX-License-Identifier: Apache-2.0
# SPDX-FileCopyrightText: Copyright contributors to the vLLM-Omni project
"""
Tests for async image generation API endpoints.

This module contains unit tests and integration tests (with mocking) for the
OpenAI-compatible async text-to-image generation API endpoints in api_server.py.
"""

import base64
import io
import json
from argparse import Namespace
from http import HTTPStatus
from types import SimpleNamespace

import pytest
from fastapi import FastAPI, HTTPException
from fastapi.testclient import TestClient
from PIL import Image
from pytest_mock import MockerFixture
from vllm import SamplingParams
from vllm.entrypoints.openai.models.protocol import BaseModelPath
from vllm.sampling_params import RequestOutputKind

from vllm_omni.entrypoints.async_omni import AsyncOmni
from vllm_omni.entrypoints.openai.api_server import router
from vllm_omni.entrypoints.openai.image_api_utils import (
    encode_image_base64,
    parse_size,
)
from vllm_omni.entrypoints.openai.images.helpers import _check_max_generated_image_size
from vllm_omni.entrypoints.openai.models.serving import _DiffusionServingModels
from vllm_omni.entrypoints.openai.serving_chat import OmniOpenAIServingChat
from vllm_omni.errors import GuardrailViolationError
from vllm_omni.inputs.data import OmniDiffusionSamplingParams

pytestmark = [pytest.mark.core_model, pytest.mark.cpu]

# Unit Tests


def test_parse_size_valid():
    """Test size parsing with valid inputs"""
    assert parse_size("1024x1024") == (1024, 1024)
    assert parse_size("512x768") == (512, 768)
    assert parse_size("256x256") == (256, 256)
    assert parse_size("1792x1024") == (1792, 1024)
    assert parse_size("1024x1792") == (1024, 1792)


def test_parse_size_invalid():
    """Test size parsing with invalid inputs"""
    with pytest.raises(ValueError, match="Invalid size format"):
        parse_size("invalid")

    with pytest.raises(ValueError, match="Invalid size format"):
        parse_size("1024")

    with pytest.raises(ValueError, match="Invalid size format"):
        parse_size("1024x")

    with pytest.raises(ValueError, match="Invalid size format"):
        parse_size("x1024")


def test_parse_size_negative():
    """Test size parsing with negative or zero dimensions"""
    with pytest.raises(ValueError, match="positive integers"):
        parse_size("0x1024")

    with pytest.raises(ValueError, match="positive integers"):
        parse_size("1024x0")

    with pytest.raises(ValueError):
        parse_size("-1024x1024")


def test_parse_size_edge_cases():
    """Test size parsing with edge cases like empty strings and non-integers"""
    # Empty string
    with pytest.raises(ValueError, match="non-empty string"):
        parse_size("")

    # Non-integer dimensions
    with pytest.raises(ValueError, match="must be integers"):
        parse_size("abc x def")

    with pytest.raises(ValueError, match="must be integers"):
        parse_size("1024.5x768.5")

    # Missing separator (user might forget 'x')
    with pytest.raises(ValueError, match="separator"):
        parse_size("1024 1024")


def test_encode_image_base64():
    """Test image encoding to base64"""
    # Create a simple test image
    img = Image.new("RGB", (64, 64), color="red")
    b64_str = encode_image_base64(img)

    # Should be valid base64
    assert isinstance(b64_str, str)
    assert len(b64_str) > 0

    # Should decode back to PNG
    decoded = base64.b64decode(b64_str)
    decoded_img = Image.open(io.BytesIO(decoded))

    # Verify properties
    assert decoded_img.size == (64, 64)
    assert decoded_img.format == "PNG"


# Integration Tests (with mocking)


class MockGenerationResult:
    """Mock result object compatible with current diffusion output shape."""

    def __init__(self, images, stage_durations=None, peak_memory_mb=0.0):
        self.images = images
        self.stage_durations = {} if stage_durations is None else stage_durations
        self.peak_memory_mb = peak_memory_mb


def _stub_engine_generate_with_metrics(engine, *, stage_durations, peak_memory_mb):
    """Stub engine.generate to return profiler metrics."""

    async def generate(*args, **kwargs):
        yield MockGenerationResult(
            [Image.new("RGB", (16, 16), color="blue")],
            stage_durations=stage_durations,
            peak_memory_mb=peak_memory_mb,
        )

    engine.generate = generate


class MockStageResult:
    """Mock multi-stage output for streaming image edit tests."""

    def __init__(self, *, stage_id, final_output_type, text="", texts=None, images=None):
        self.stage_id = stage_id
        self.final_output_type = final_output_type
        self.images = images or []
        if texts is not None:
            outputs = [SimpleNamespace(text=item, index=index) for index, item in enumerate(texts)]
        elif text:
            outputs = [SimpleNamespace(text=text, index=0)]
        else:
            outputs = []
        self.outputs = outputs
        self.stage_durations = {}
        self.peak_memory_mb = 0.0


class FakeAsyncOmni:
    """Fake AsyncOmni that yields a single diffusion output."""

    def __init__(self, images=None):
        self.stage_configs = [
            SimpleNamespace(stage_type="llm", is_comprehension=True),
            SimpleNamespace(stage_type="diffusion", is_comprehension=False),
        ]
        self.default_sampling_params_list = [SamplingParams(temperature=0.1), OmniDiffusionSamplingParams()]
        self.captured_sampling_params_list = None
        self.captured_prompt = None
        self._images = images or [Image.new("RGB", (64, 64), color="green")]

    async def generate(self, prompt, request_id, sampling_params=None, sampling_params_list=None, **kwargs):
        if sampling_params_list is not None:
            self.captured_sampling_params_list = sampling_params_list
        else:
            self.captured_sampling_params_list = [sampling_params]
        self.captured_prompt = prompt
        images = [img.copy() for img in self._images]
        yield MockGenerationResult(images)

    def __class_getitem__(cls, item):
        return cls


@pytest.fixture
def mock_async_diffusion(mocker: MockerFixture):
    """Mock diffusion engine that matches the current async-generator API."""

    class MockAsyncDiffusion:
        def __init__(self) -> None:
            self.is_running = True
            self.check_health = mocker.AsyncMock()
            self.captured_sampling_params_list = None
            self.captured_prompt = None
            self.generate_calls = 0

        async def generate(self, **kwargs):
            self.generate_calls += 1
            n = kwargs["sampling_params_list"][0].num_outputs_per_prompt
            self.captured_sampling_params_list = kwargs["sampling_params_list"]
            self.captured_prompt = kwargs["prompt"]
            images = [Image.new("RGB", (64, 64), color="blue") for _ in range(n)]
            yield MockGenerationResult(images)

    return MockAsyncDiffusion()


@pytest.fixture
def test_client(mock_async_diffusion):
    """Create test client with mocked async diffusion engine"""
    from fastapi import FastAPI

    from vllm_omni.entrypoints.openai.api_server import router

    app = FastAPI()
    app.include_router(router)

    # Set up app state with diffusion engine
    app.state.engine_client = mock_async_diffusion
    app.state.diffusion_engine = mock_async_diffusion  # Also set for health endpoint
    app.state.stage_configs = [SimpleNamespace(stage_type="diffusion")]
    from vllm.entrypoints.openai.models.protocol import BaseModelPath

    from vllm_omni.entrypoints.openai.models.serving import _DiffusionServingModels

    app.state.openai_serving_models = _DiffusionServingModels(
        [BaseModelPath(name="Qwen/Qwen-Image", model_path="Qwen/Qwen-Image")]
    )
    app.state.args = Namespace(
        default_sampling_params='{"0": {"num_inference_steps":4, "guidance_scale":7.5, "generator_device":"cpu"}}',
        max_generated_image_size=1024 * 1792,
    )

    return TestClient(app)


@pytest.fixture
def lingbot_test_client(test_client):
    test_client.app.state.stage_configs = [
        SimpleNamespace(
            stage_type="diffusion",
            engine_args={"model_class_name": "LingBotVideoPipeline"},
        )
    ]
    return test_client


@pytest.fixture
def async_omni_test_client():
    """Create test client with mocked AsyncOmni engine."""
    from fastapi import FastAPI

    from vllm_omni.entrypoints.async_omni import AsyncOmni
    from vllm_omni.entrypoints.openai.api_server import router
    from vllm_omni.entrypoints.openai.serving_chat import OmniOpenAIServingChat

    class FakeAsyncOmniClass(AsyncOmni):
        def __init__(self):
            stage_configs = [
                SimpleNamespace(stage_type="llm", is_comprehension=True),
                SimpleNamespace(stage_type="diffusion", is_comprehension=False),
            ]
            default_sampling_params_list = [
                SamplingParams(temperature=0.1),
                OmniDiffusionSamplingParams(
                    num_inference_steps=4,
                    guidance_scale=7.5,
                    generator_device="cpu",
                ),
            ]
            self.engine = SimpleNamespace(
                stage_configs=stage_configs,
                default_sampling_params_list=default_sampling_params_list,
            )
            self.default_sampling_params_list = default_sampling_params_list
            self.captured_sampling_params_list = None
            self.captured_prompt = None
            self._images = [Image.new("RGB", (64, 64), color="green")]
            self.od_config = SimpleNamespace(supports_multimodal_inputs=True)

        async def generate(self, prompt, request_id, sampling_params=None, sampling_params_list=None, **kwargs):
            if sampling_params_list is not None:
                self.captured_sampling_params_list = sampling_params_list
            else:
                self.captured_sampling_params_list = [sampling_params]
            self.captured_prompt = prompt
            images = [img.copy() for img in self._images]
            yield MockGenerationResult(images)

        def __class_getitem__(cls, item):
            return cls

        def get_diffusion_od_config(self):
            return self.od_config

    app = FastAPI()
    app.include_router(router)

    engine = FakeAsyncOmniClass()
    chat_handler = object.__new__(OmniOpenAIServingChat)
    chat_handler.engine_client = engine
    chat_handler._diffusion_engine = None
    app.state.openai_serving_chat = chat_handler
    app.state.engine_client = engine
    app.state.stage_configs = [
        SimpleNamespace(stage_type="llm"),
        SimpleNamespace(stage_type="diffusion"),
    ]
    app.state.args = Namespace(
        default_sampling_params='{"1": {"num_inference_steps":4, "guidance_scale":7.5, "generator_device":"cpu"}}',
        max_generated_image_size=1048576,  # 1024*1024 to support resolution tests
    )
    return TestClient(app)


@pytest.fixture
def async_omni_rgba_test_client():
    """Create test client with mocked AsyncOmni engine returning RGBA output."""
    from fastapi import FastAPI

    from vllm_omni.entrypoints.async_omni import AsyncOmni
    from vllm_omni.entrypoints.openai.api_server import router
    from vllm_omni.entrypoints.openai.serving_chat import OmniOpenAIServingChat

    class FakeAsyncOmniClass(AsyncOmni):
        def __init__(self):
            stage_configs = [
                SimpleNamespace(stage_type="llm", is_comprehension=True),
                SimpleNamespace(stage_type="diffusion", is_comprehension=False),
            ]
            default_sampling_params_list = [
                SamplingParams(temperature=0.1),
                OmniDiffusionSamplingParams(),
            ]
            self.engine = SimpleNamespace(
                stage_configs=stage_configs,
                default_sampling_params_list=default_sampling_params_list,
            )
            self.default_sampling_params_list = default_sampling_params_list
            self.captured_sampling_params_list = None
            self.captured_prompt = None
            self._images = [Image.new("RGBA", (64, 64), color=(0, 255, 0, 128))]
            self.od_config = SimpleNamespace(supports_multimodal_inputs=True)

        async def generate(self, prompt, request_id, sampling_params=None, sampling_params_list=None, **kwargs):
            if sampling_params_list is not None:
                self.captured_sampling_params_list = sampling_params_list
            else:
                self.captured_sampling_params_list = [sampling_params]
            self.captured_prompt = prompt
            images = [img.copy() for img in self._images]
            yield MockGenerationResult(images)

        def __class_getitem__(cls, item):
            return cls

        def get_diffusion_od_config(self):
            return self.od_config

    app = FastAPI()
    app.include_router(router)

    engine = FakeAsyncOmniClass()
    chat_handler = object.__new__(OmniOpenAIServingChat)
    chat_handler.engine_client = engine
    chat_handler._diffusion_engine = None
    app.state.openai_serving_chat = chat_handler
    app.state.engine_client = engine
    app.state.stage_configs = [
        SimpleNamespace(stage_type="llm"),
        SimpleNamespace(stage_type="diffusion"),
    ]
    app.state.args = Namespace(
        default_sampling_params='{"1": {"num_inference_steps":4, "guidance_scale":7.5, "generator_device":"cpu"}}',
        max_generated_image_size=1048576,
    )
    return TestClient(app)


@pytest.fixture
def async_omni_stage_configs_only_client():
    """Create test client with refactored AsyncOmni compatibility surface only."""
    from fastapi import FastAPI

    from vllm_omni.entrypoints.async_omni import AsyncOmni
    from vllm_omni.entrypoints.openai.api_server import router
    from vllm_omni.entrypoints.openai.serving_chat import OmniOpenAIServingChat

    class FakeAsyncOmniClass(AsyncOmni):
        def __init__(self):
            stage_configs = [
                SimpleNamespace(stage_type="llm", is_comprehension=True),
                SimpleNamespace(stage_type="diffusion", is_comprehension=False),
            ]
            default_sampling_params_list = [
                SamplingParams(temperature=0.1),
                OmniDiffusionSamplingParams(),
            ]
            self.engine = SimpleNamespace(
                stage_configs=stage_configs,
                default_sampling_params_list=default_sampling_params_list,
            )
            self.default_sampling_params_list = default_sampling_params_list
            self.captured_sampling_params_list = None
            self.captured_prompt = None
            self._images = [Image.new("RGB", (64, 64), color="green")]
            self.od_config = SimpleNamespace(supports_multimodal_inputs=True)

        async def generate(self, prompt, request_id, sampling_params=None, sampling_params_list=None, **kwargs):
            if sampling_params_list is not None:
                self.captured_sampling_params_list = sampling_params_list
            else:
                self.captured_sampling_params_list = [sampling_params]
            self.captured_prompt = prompt
            images = [img.copy() for img in self._images]
            yield MockGenerationResult(images)

        def __class_getitem__(cls, item):
            return cls

        def get_diffusion_od_config(self):
            return self.od_config

    app = FastAPI()
    app.include_router(router)

    engine = FakeAsyncOmniClass()
    assert not hasattr(engine, "stage_list")
    app.state.engine_client = engine
    chat_handler = object.__new__(OmniOpenAIServingChat)
    chat_handler.engine_client = engine
    chat_handler._diffusion_engine = None
    app.state.openai_serving_chat = chat_handler
    app.state.args = Namespace(
        default_sampling_params='{"1": {"num_inference_steps":4, "guidance_scale":7.5, "generator_device":"cpu"}}',
        max_generated_image_size=1024 * 1792,
    )
    return TestClient(app)


@pytest.fixture
def streaming_image_edit_client():
    """Create a multi-stage client whose engine yields AR text before image output."""
    from fastapi import FastAPI

    from vllm_omni.entrypoints.async_omni import AsyncOmni
    from vllm_omni.entrypoints.openai.api_server import router
    from vllm_omni.entrypoints.openai.serving_chat import OmniOpenAIServingChat

    class FakeAsyncOmniClass(AsyncOmni):
        def __init__(self):
            stage_configs = [
                SimpleNamespace(stage_type="llm", is_comprehension=True),
                SimpleNamespace(stage_type="diffusion", is_comprehension=False),
            ]
            default_sampling_params_list = [
                SamplingParams(temperature=0.1),
                OmniDiffusionSamplingParams(),
            ]
            self.engine = SimpleNamespace(
                stage_configs=stage_configs,
                default_sampling_params_list=default_sampling_params_list,
            )
            self.default_sampling_params_list = default_sampling_params_list
            self.captured_sampling_params_list = None
            self.captured_prompt = None
            self.od_config = SimpleNamespace(supports_multimodal_inputs=True)

        async def generate(self, prompt, request_id, sampling_params=None, sampling_params_list=None, **kwargs):
            self.captured_prompt = prompt
            self.captured_sampling_params_list = sampling_params_list or [sampling_params]
            assert self.captured_sampling_params_list[0].output_kind == RequestOutputKind.DELTA
            yield MockStageResult(stage_id=0, final_output_type="text", text="recap")
            yield MockStageResult(stage_id=0, final_output_type="text", text=" done")
            yield MockStageResult(
                stage_id=1,
                final_output_type="image",
                images=[Image.new("RGB", (32, 24), color="purple")],
            )

        def __class_getitem__(cls, item):
            return cls

        def get_diffusion_od_config(self):
            return self.od_config

    app = FastAPI()
    app.include_router(router)

    engine = FakeAsyncOmniClass()
    chat_handler = object.__new__(OmniOpenAIServingChat)
    chat_handler.engine_client = engine
    chat_handler._diffusion_engine = None
    app.state.openai_serving_chat = chat_handler
    app.state.engine_client = engine
    app.state.stage_configs = [
        SimpleNamespace(stage_type="llm"),
        SimpleNamespace(stage_type="diffusion"),
    ]
    app.state.args = Namespace(
        default_sampling_params='{"1": {"num_inference_steps":4, "guidance_scale":7.5, "generator_device":"cpu"}}',
        max_generated_image_size=1024 * 1792,
    )
    return TestClient(app)


def test_health_endpoint(test_client):
    """Test health check endpoint for diffusion mode"""
    response = test_client.get("/health")
    assert response.status_code == 200
    data = response.json()
    assert data["status"] == "healthy"


def test_health_endpoint_no_engine():
    """Test health check endpoint when no engine is initialized"""
    from fastapi import FastAPI

    from vllm_omni.entrypoints.openai.api_server import router

    app = FastAPI()
    app.include_router(router)
    # Don't set any engine

    client = TestClient(app)
    response = client.get("/health")
    assert response.status_code == 503
    data = response.json()
    assert data["status"] == "unhealthy"


def test_health_endpoint_dead_engine():
    """Health returns 503 when the engine raises EngineDeadError."""
    from unittest.mock import AsyncMock

    from fastapi import FastAPI
    from vllm.v1.engine.exceptions import EngineDeadError

    from vllm_omni.entrypoints.openai.api_server import router

    app = FastAPI()
    app.include_router(router)

    dead_engine = AsyncMock()
    dead_engine.check_health = AsyncMock(side_effect=EngineDeadError())
    app.state.engine_client = dead_engine

    client = TestClient(app)
    response = client.get("/health")
    assert response.status_code == 503
    data = response.json()
    assert data["status"] == "unhealthy"


def test_models_endpoint(test_client):
    """Test /v1/models endpoint for diffusion mode"""
    response = test_client.get("/v1/models")
    assert response.status_code == 200
    data = response.json()
    assert data["object"] == "list"
    assert len(data["data"]) == 1
    assert data["data"][0]["id"] == "Qwen/Qwen-Image"
    assert data["data"][0]["object"] == "model"


def test_models_endpoint_no_engine():
    """Test /v1/models endpoint when no engine is initialized"""
    from fastapi import FastAPI

    from vllm_omni.entrypoints.openai.api_server import router

    app = FastAPI()
    app.include_router(router)
    # Don't set any engine

    client = TestClient(app)
    response = client.get("/v1/models")
    assert response.status_code == 200
    data = response.json()
    assert data["object"] == "list"
    assert len(data["data"]) == 0


def test_generate_single_image(test_client):
    """Test generating a single image"""
    # Single-stage path should not require openai_serving_chat.
    assert not hasattr(test_client.app.state, "openai_serving_chat")

    response = test_client.post(
        "/v1/images/generations",
        json={
            "prompt": "a cat",
            "n": 1,
            "size": "1024x1024",
        },
    )
    assert response.status_code == 200
    data = response.json()

    # Check response structure
    assert "created" in data
    assert isinstance(data["created"], int)
    assert "data" in data
    assert len(data["data"]) == 1
    assert "b64_json" in data["data"][0]

    # Verify image can be decoded
    img_bytes = base64.b64decode(data["data"][0]["b64_json"])
    img = Image.open(io.BytesIO(img_bytes))
    assert img.size == (64, 64)  # Our mock returns 64x64 images
    assert test_client.app.state.engine_client.captured_prompt["modalities"] == ["image"]


def test_generate_images_guardrail_error_returns_400(test_client, mock_async_diffusion):
    async def blocked_generate(**kwargs):
        raise GuardrailViolationError("Input was blocked by Cosmos3 guardrails.")
        yield MockGenerationResult([])  # pragma: no cover

    mock_async_diffusion.generate = blocked_generate
    response = test_client.post(
        "/v1/images/generations",
        json={
            "prompt": "blocked prompt",
            "n": 1,
            "size": "1024x1024",
        },
    )
    assert response.status_code == 400
    assert response.json()["detail"] == "Input was blocked by Cosmos3 guardrails."


def test_generate_images_async_omni_sampling_params(async_omni_test_client):
    """Test AsyncOmni path uses per-stage sampling params."""
    response = async_omni_test_client.post(
        "/v1/images/generations",
        json={
            "prompt": "a cat",
            "n": 2,
            "size": "256x256",
            "seed": 7,
        },
    )
    assert response.status_code == 200
    engine = async_omni_test_client.app.state.engine_client
    captured = engine.captured_sampling_params_list
    assert captured is not None
    assert len(captured) == 2
    assert captured[0].temperature == 0.1
    assert captured[1].num_outputs_per_prompt == 2
    assert captured[1].height == 256
    assert captured[1].width == 256
    assert captured[1].seed == 7


def test_generate_images_async_omni_stage_configs_only(async_omni_stage_configs_only_client):
    """Regression: image generation accepts refactored AsyncOmni without stage_list."""
    response = async_omni_stage_configs_only_client.post(
        "/v1/images/generations",
        json={
            "prompt": "a castle",
            "n": 1,
            "size": "256x256",
            "seed": 11,
        },
    )
    assert response.status_code == 200
    data = response.json()
    assert len(data["data"]) == 1
    engine = async_omni_stage_configs_only_client.app.state.engine_client
    captured = engine.captured_sampling_params_list
    assert captured is not None
    assert len(captured) == 2
    assert captured[1].seed == 11


def test_multistage_images_async_omni_construction(async_omni_test_client):
    """Regression: multistage image generation builds the expected chat-style payload."""
    response = async_omni_test_client.post(
        "/v1/images/generations",
        json={
            "prompt": "a cat",
            "n": 2,
            "size": "128x256",
            "seed": 7,
            "num_inference_steps": 12,
            "guidance_scale": 6.5,
        },
    )
    assert response.status_code == 200

    engine = async_omni_test_client.app.state.engine_client
    captured_prompt = engine.captured_prompt
    assert captured_prompt["prompt"] == "a cat"
    assert captured_prompt["modalities"] == ["image"]
    assert captured_prompt["mm_processor_kwargs"] == {
        "target_h": 256,
        "target_w": 128,
    }

    captured = engine.captured_sampling_params_list
    assert captured is not None
    assert len(captured) == 2
    assert captured[0].temperature == 0.1
    assert captured[0].seed == 7
    assert captured[1].num_outputs_per_prompt == 2
    assert captured[1].width == 128
    assert captured[1].height == 256
    assert captured[1].seed == 7
    assert captured[1].num_inference_steps == 12
    assert captured[1].guidance_scale == 6.5


def test_generate_images_async_omni_glm_image_sets_stage0_max_tokens():
    """GLM-Image multistage: stage-0 gets target_h/w from requested size.

    max_tokens comes from the deploy YAML default (upper-bound ceiling),
    NOT computed dynamically from height/width.
    """

    class FakeAsyncOmniClass(AsyncOmni):
        def __init__(self):
            stage_configs = [
                SimpleNamespace(stage_type="llm", is_comprehension=True, model_arch="GlmImageForConditionalGeneration"),
                SimpleNamespace(stage_type="diffusion", is_comprehension=False, model_arch="GlmImagePipeline"),
            ]
            # YAML default max_tokens for GLM-Image AR stage (upper bound for 2048x2048 t2i)
            default_sampling_params_list = [
                SamplingParams(temperature=0.1, seed=42, max_tokens=4353),
                OmniDiffusionSamplingParams(height=1024, width=1024),
            ]
            self.engine = SimpleNamespace(
                stage_configs=stage_configs,
                default_sampling_params_list=default_sampling_params_list,
            )
            self.default_sampling_params_list = default_sampling_params_list
            self.captured_sampling_params_list = None
            self.captured_prompt = None
            self._images = [Image.new("RGB", (64, 64), color="green")]
            self.od_config = SimpleNamespace(supports_multimodal_inputs=True)

        async def generate(self, prompt, request_id, sampling_params=None, sampling_params_list=None, **kwargs):
            self.captured_sampling_params_list = (
                sampling_params_list if sampling_params_list is not None else [sampling_params]
            )
            self.captured_prompt = prompt
            yield MockGenerationResult([img.copy() for img in self._images])

        def __class_getitem__(cls, item):
            return cls

        def get_diffusion_od_config(self):
            return self.od_config

    app = FastAPI()
    app.include_router(router)
    engine = FakeAsyncOmniClass()
    chat_handler = object.__new__(OmniOpenAIServingChat)
    chat_handler.engine_client = engine
    chat_handler._diffusion_engine = None
    app.state.openai_serving_chat = chat_handler
    app.state.engine_client = engine
    app.state.stage_configs = [
        SimpleNamespace(stage_type="llm", model_arch="GlmImageForConditionalGeneration"),
        SimpleNamespace(stage_type="diffusion", model_arch="GlmImagePipeline"),
    ]
    app.state.openai_serving_models = _DiffusionServingModels(
        [BaseModelPath(name="THUDM/GLM-4.5V", model_path="THUDM/GLM-4.5V")]
    )
    app.state.args = Namespace(
        default_sampling_params='{"1": {"num_inference_steps":4, "guidance_scale":7.5, "generator_device":"cpu"}}',
        max_generated_image_size=1048576,
    )
    client = TestClient(app)

    response = client.post(
        "/v1/images/generations",
        json={
            "prompt": "a coral reef",
            "n": 1,
            "size": "1024x1024",
            "seed": 7,
        },
    )
    assert response.status_code == 200

    captured = engine.captured_sampling_params_list
    assert captured is not None
    assert len(captured) == 2
    # max_tokens comes from YAML default, not computed dynamically
    assert captured[0].max_tokens == 4353
    assert captured[0].extra_args["target_h"] == 1024
    assert captured[0].extra_args["target_w"] == 1024
    assert captured[1].height == 1024
    assert captured[1].width == 1024


def test_image_edits_async_omni_stage_configs_only(async_omni_stage_configs_only_client):
    """Regression: image edits accepts refactored AsyncOmni without stage_list."""
    img_bytes = make_test_image_bytes((16, 16))
    response = async_omni_stage_configs_only_client.post(
        "/v1/images/edits",
        files=[("image", img_bytes)],
        data={
            "prompt": "edit me",
            "size": "auto",
        },
    )
    assert response.status_code == 200
    engine = async_omni_stage_configs_only_client.app.state.engine_client
    captured = engine.captured_sampling_params_list
    assert captured is not None
    assert len(captured) == 2


def _parse_sse_payloads(body: str):
    payloads = []
    for line in body.splitlines():
        if not line.startswith("data: "):
            continue
        data = line[len("data: ") :]
        payloads.append(data if data == "[DONE]" else json.loads(data))
    return payloads


def test_image_edits_streaming_returns_ar_delta_then_image(streaming_image_edit_client):
    img_bytes = make_test_image_bytes((16, 16))
    response = streaming_image_edit_client.post(
        "/v1/images/edits",
        files=[("image", img_bytes)],
        data={
            "prompt": "edit me",
            "size": "auto",
            "stream": "true",
            "output_format": "png",
        },
    )

    assert response.status_code == 200
    assert response.headers["content-type"].startswith("text/event-stream")

    payloads = _parse_sse_payloads(response.text)
    assert [p["type"] if isinstance(p, dict) and "type" in p else p for p in payloads] == [
        "ar_delta",
        "ar_delta",
        "image",
        "[DONE]",
    ]
    assert payloads[0]["delta"] == "recap"
    assert payloads[0]["index"] == 0
    assert payloads[1]["delta"] == " done"
    assert payloads[2]["output_format"] == "png"
    assert payloads[2]["size"] == "16x16"

    image_payload = payloads[2]["data"][0]
    img = Image.open(io.BytesIO(base64.b64decode(image_payload["b64_json"])))
    assert img.size == (32, 24)


def test_image_edits_streaming_ar_delta_chunks_include_index(streaming_image_edit_client):
    async def generate_multi_output_delta(
        prompt, request_id, sampling_params=None, sampling_params_list=None, **kwargs
    ):
        yield MockStageResult(stage_id=0, final_output_type="text", texts=["first", "second"])
        yield MockStageResult(
            stage_id=1,
            final_output_type="image",
            images=[Image.new("RGB", (32, 24), color="purple")],
        )

    streaming_image_edit_client.app.state.engine_client.generate = generate_multi_output_delta
    img_bytes = make_test_image_bytes((16, 16))
    response = streaming_image_edit_client.post(
        "/v1/images/edits",
        files=[("image", img_bytes)],
        data={
            "prompt": "edit me",
            "stream": "true",
        },
    )

    assert response.status_code == 200
    payloads = _parse_sse_payloads(response.text)
    assert [(payloads[0]["index"], payloads[0]["delta"]), (payloads[1]["index"], payloads[1]["delta"])] == [
        (0, "first"),
        (1, "second"),
    ]


def test_image_edits_streaming_errors_without_final_image(streaming_image_edit_client):
    async def generate_without_image(prompt, request_id, sampling_params=None, sampling_params_list=None, **kwargs):
        yield MockStageResult(stage_id=0, final_output_type="text", text="recap")

    streaming_image_edit_client.app.state.engine_client.generate = generate_without_image
    img_bytes = make_test_image_bytes((16, 16))
    response = streaming_image_edit_client.post(
        "/v1/images/edits",
        files=[("image", img_bytes)],
        data={
            "prompt": "edit me",
            "stream": "true",
        },
    )

    assert response.status_code == 200
    payloads = _parse_sse_payloads(response.text)
    assert payloads[0]["type"] == "ar_delta"
    assert payloads[1]["object"] == "error"
    assert "without a final image" in payloads[1]["error"]["message"]
    assert payloads[2] == "[DONE]"


def test_image_edits_streaming_errors_on_empty_final_image(streaming_image_edit_client):
    async def generate_empty_image(prompt, request_id, sampling_params=None, sampling_params_list=None, **kwargs):
        yield MockStageResult(stage_id=0, final_output_type="text", text="recap")
        yield MockStageResult(stage_id=1, final_output_type="image", images=[])

    streaming_image_edit_client.app.state.engine_client.generate = generate_empty_image
    img_bytes = make_test_image_bytes((16, 16))
    response = streaming_image_edit_client.post(
        "/v1/images/edits",
        files=[("image", img_bytes)],
        data={
            "prompt": "edit me",
            "stream": "true",
        },
    )

    assert response.status_code == 200
    payloads = _parse_sse_payloads(response.text)
    assert payloads[0]["type"] == "ar_delta"
    assert payloads[1]["object"] == "error"
    assert "empty final image" in payloads[1]["error"]["message"]
    assert payloads[2] == "[DONE]"


def test_image_edits_streaming_guardrail_error_uses_400(streaming_image_edit_client):
    async def generate_guardrail_error(prompt, request_id, sampling_params=None, sampling_params_list=None, **kwargs):
        raise GuardrailViolationError("Input was blocked by Cosmos3 guardrails.")
        yield MockStageResult(stage_id=1, final_output_type="image", images=[])  # pragma: no cover

    streaming_image_edit_client.app.state.engine_client.generate = generate_guardrail_error
    img_bytes = make_test_image_bytes((16, 16))
    response = streaming_image_edit_client.post(
        "/v1/images/edits",
        files=[("image", img_bytes)],
        data={
            "prompt": "blocked prompt",
            "stream": "true",
        },
    )

    assert response.status_code == 200
    payloads = _parse_sse_payloads(response.text)
    assert payloads[0]["object"] == "error"
    assert payloads[0]["error"]["message"] == "Input was blocked by Cosmos3 guardrails."
    assert payloads[0]["error"]["type"] == "BadRequestError"
    assert payloads[0]["error"]["code"] == 400
    assert payloads[1] == "[DONE]"


def test_image_edits_streaming_rejects_single_stage(test_client):
    img_bytes = make_test_image_bytes((16, 16))
    response = test_client.post(
        "/v1/images/edits",
        files=[("image", img_bytes)],
        data={
            "prompt": "edit me",
            "stream": "true",
        },
    )

    assert response.status_code == 400
    assert "multi-stage" in response.json()["detail"]


def test_image_edits_streaming_rejects_single_stage_before_loading_url(test_client):
    response = test_client.post(
        "/v1/images/edits",
        data={
            "prompt": "edit me",
            "url": "https://example.invalid/not-fetched.png",
            "stream": "true",
        },
    )

    assert response.status_code == 400
    assert "multi-stage" in response.json()["detail"]


def test_generate_images_returns_metrics_single_stage(test_client):
    """Single-stage /v1/images/generations copies getattr metrics onto the response."""
    stage_durations = {"queue_wait_ms": 1.0, "stage_0_gen_ms": 2.0}
    peak_memory_mb = 1024.0
    _stub_engine_generate_with_metrics(
        test_client.app.state.engine_client,
        stage_durations=stage_durations,
        peak_memory_mb=peak_memory_mb,
    )

    response = test_client.post(
        "/v1/images/generations",
        json={"prompt": "a cat", "n": 1, "size": "256x256"},
    )
    assert response.status_code == 200
    assert response.json()["metrics"] == {
        "stage_durations": stage_durations,
        "peak_memory_mb": peak_memory_mb,
    }


def test_generate_images_returns_metrics_multistage(async_omni_test_client):
    """Multi-stage /v1/images/generations unpacks generate_diffusion_images metrics."""
    stage_durations = {
        "queue_wait_ms": 1.0,
        "preprocess_ms": 2.0,
        "stage_0_gen_ms": 3.0,
        "stage_1_gen_ms": 4.0,
    }
    peak_memory_mb = 2048.0
    _stub_engine_generate_with_metrics(
        async_omni_test_client.app.state.engine_client,
        stage_durations=stage_durations,
        peak_memory_mb=peak_memory_mb,
    )

    response = async_omni_test_client.post(
        "/v1/images/generations",
        json={"prompt": "a cat", "n": 1, "size": "256x256"},
    )
    assert response.status_code == 200
    assert response.json()["metrics"] == {
        "stage_durations": stage_durations,
        "peak_memory_mb": peak_memory_mb,
    }


def test_generate_images_max_size_rejected(async_omni_test_client):
    """Test that a size exceeding max_generated_image_size returns 400."""
    response = async_omni_test_client.post(
        "/v1/images/generations",
        json={
            "prompt": "a cat",
            "size": "2048x2048",  # 4,194,304 pixels > max_generated_image_size (1,048,576)
        },
    )
    assert response.status_code == 400


def test_generate_multiple_images(test_client):
    """Test generating multiple images"""
    response = test_client.post(
        "/v1/images/generations",
        json={
            "prompt": "a dog",
            "n": 3,
            "size": "512x512",
        },
    )
    assert response.status_code == 200
    data = response.json()
    assert len(data["data"]) == 3

    # All images should be valid
    for img_data in data["data"]:
        assert "b64_json" in img_data
        img_bytes = base64.b64decode(img_data["b64_json"])
        img = Image.open(io.BytesIO(img_bytes))
        assert img.format == "PNG"


def test_with_negative_prompt(test_client):
    """Test with negative prompt"""
    response = test_client.post(
        "/v1/images/generations",
        json={
            "prompt": "beautiful landscape",
            "negative_prompt": "blurry, low quality",
            "size": "1024x1024",
        },
    )
    assert response.status_code == 200


def test_with_seed(test_client):
    """Test with seed for reproducibility"""
    response = test_client.post(
        "/v1/images/generations",
        json={
            "prompt": "a tree",
            "seed": 42,
            "size": "1024x1024",
        },
    )
    assert response.status_code == 200


def test_with_seed_zero(test_client):
    """Test with seed=0 for reproducibility"""
    response = test_client.post(
        "/v1/images/generations",
        json={
            "prompt": "a tree",
            "seed": 0,
            "size": "1024x1024",
        },
    )
    assert response.status_code == 200
    engine = test_client.app.state.engine_client
    captured = engine.captured_sampling_params_list[0]
    # Verify that seed=0 is correctly passed
    assert captured.seed == 0, (
        f"Expected seed=0, but got seed={captured.seed}. This indicates the bug where seed=0 is treated as falsy."
    )


def test_with_custom_parameters(test_client):
    """Test with custom diffusion parameters"""
    response = test_client.post(
        "/v1/images/generations",
        json={
            "prompt": "a mountain",
            "size": "1024x1024",
            "num_inference_steps": 100,
            "true_cfg_scale": 5.5,
            "seed": 123,
        },
    )
    assert response.status_code == 200


def test_flow_shift_forwarded_to_extra_args(test_client):
    """flow_shift must reach the diffusion sampling params via extra_args.

    Regression: ``ImageGenerationRequest`` had no ``flow_shift`` field and the
    single-stage handler never forwarded it, so a request like
    ``{"flow_shift": 10.0}`` was silently dropped and Cosmos3 T2I always ran at
    its hardcoded per-mode default shift. The pipeline reads
    ``extra_args["flow_shift"]`` (via ``_get_sp_param``), so it must land there.
    """
    response = test_client.post(
        "/v1/images/generations",
        json={
            "prompt": "a robot in a lab",
            "size": "960x960",
            "num_inference_steps": 50,
            "guidance_scale": 4.0,
            "flow_shift": 10.0,
        },
    )
    assert response.status_code == 200
    captured = test_client.app.state.engine_client.captured_sampling_params_list[0]
    assert captured.extra_args["flow_shift"] == 10.0


def test_flow_shift_absent_when_not_requested(test_client):
    """Omitting flow_shift must not inject an override, so the pipeline keeps
    its per-mode default (e.g. Cosmos3 T2I shift=3.0)."""
    response = test_client.post(
        "/v1/images/generations",
        json={"prompt": "a tree", "size": "1024x1024"},
    )
    assert response.status_code == 200
    captured = test_client.app.state.engine_client.captured_sampling_params_list[0]
    assert "flow_shift" not in (captured.extra_args or {})


def test_invalid_size(test_client):
    """Test with invalid size parameter - rejected by Pydantic"""
    response = test_client.post(
        "/v1/images/generations",
        json={
            "prompt": "a cat",
            "size": "invalid",
        },
    )
    # Pydantic validation errors return 422 (Unprocessable Entity)
    # "invalid" has no "x" so Pydantic rejects it
    assert response.status_code == 422
    # Check error detail contains size validation message
    detail = str(response.json()["detail"])
    assert "size" in detail.lower() or "invalid" in detail.lower()


def test_invalid_size_parse_error(test_client):
    """Test with malformed size - passes Pydantic but fails parse_size()"""
    response = test_client.post(
        "/v1/images/generations",
        json={
            "prompt": "a cat",
            "size": "1024x",  # Has "x" so Pydantic accepts, but parse_size() rejects
        },
    )
    # parse_size() raises ValueError → endpoint converts to 400 (Bad Request)
    assert response.status_code == 400
    detail = str(response.json()["detail"])
    assert "size" in detail.lower() or "invalid" in detail.lower()


def test_missing_prompt(test_client):
    """Test with missing required prompt field"""
    response = test_client.post(
        "/v1/images/generations",
        json={
            "size": "1024x1024",
        },
    )
    # Pydantic validation error
    assert response.status_code == 422


def test_invalid_n_parameter(test_client):
    """Test with invalid n parameter (out of range)"""
    # n < 1
    response = test_client.post(
        "/v1/images/generations",
        json={
            "prompt": "a cat",
            "n": 0,
        },
    )
    assert response.status_code == 422

    # n > 10
    response = test_client.post(
        "/v1/images/generations",
        json={
            "prompt": "a cat",
            "n": 11,
        },
    )
    assert response.status_code == 422


def test_url_response_format_not_supported(test_client):
    """Test that URL format returns error"""
    response = test_client.post(
        "/v1/images/generations",
        json={
            "prompt": "a cat",
            "response_format": "url",
        },
    )
    # Pydantic validation errors return 422 (Unprocessable Entity)
    assert response.status_code == 422
    # Check error mentions response_format or b64_json
    detail = str(response.json()["detail"])
    assert "b64_json" in detail.lower() or "response" in detail.lower()


def test_model_not_loaded():
    """Test error when diffusion engine is not initialized"""
    from fastapi import FastAPI

    from vllm_omni.entrypoints.openai.api_server import router

    app = FastAPI()
    app.include_router(router)
    # Don't set diffusion_engine to simulate uninitialized state
    app.state.diffusion_engine = None

    client = TestClient(app)
    response = client.post(
        "/v1/images/generations",
        json={
            "prompt": "a cat",
        },
    )
    assert response.status_code == 503
    assert "not initialized" in response.json()["detail"].lower()


def test_different_image_sizes(test_client):
    """Test various valid image sizes"""
    sizes = ["256x256", "512x512", "1024x1024", "1792x1024", "1024x1792"]

    for size in sizes:
        response = test_client.post(
            "/v1/images/generations",
            json={
                "prompt": "a test image",
                "size": size,
            },
        )
        assert response.status_code == 200, f"Failed for size {size}"


def test_parameter_validation():
    """Test Pydantic model validation"""
    from vllm_omni.entrypoints.openai.protocol.images import ImageGenerationRequest

    # Valid request - optional parameters default to None
    req = ImageGenerationRequest(prompt="test")
    assert req.prompt == "test"
    assert req.n == 1
    assert req.model is None
    assert req.size is None  # Engine will use model defaults
    assert req.num_inference_steps is None  # Engine will use model defaults
    assert req.true_cfg_scale is None  # Engine will use model defaults

    # Invalid num_inference_steps (out of range)
    with pytest.raises(ValueError):
        ImageGenerationRequest(prompt="test", num_inference_steps=0)

    with pytest.raises(ValueError):
        ImageGenerationRequest(prompt="test", num_inference_steps=201)

    # Invalid guidance_scale (out of range)
    with pytest.raises(ValueError):
        ImageGenerationRequest(prompt="test", guidance_scale=-1.0)

    with pytest.raises(ValueError):
        ImageGenerationRequest(prompt="test", guidance_scale=21.0)

    # Invalid layers for layered models (must stay within the backend-supported range)
    with pytest.raises(ValueError):
        ImageGenerationRequest(prompt="test", layers=1)

    with pytest.raises(ValueError):
        ImageGenerationRequest(prompt="test", layers=11)


# Pass-Through Tests


def test_parameters_passed_through(test_client, mock_async_diffusion):
    """Verify all parameters passed through without modification"""
    response = test_client.post(
        "/v1/images/generations",
        json={
            "prompt": "test",
            "num_inference_steps": 100,
            "guidance_scale": 7.5,
            "true_cfg_scale": 3.0,
            "seed": 42,
        },
    )
    assert response.status_code == 200

    assert mock_async_diffusion.generate_calls == 1
    captured = mock_async_diffusion.captured_sampling_params_list[0]
    assert captured.num_inference_steps == 100
    assert captured.guidance_scale == 7.5
    assert captured.true_cfg_scale == 3.0
    assert captured.seed == 42


def test_model_field_omitted_works(test_client):
    """Test that omitting model field works"""
    response = test_client.post(
        "/v1/images/generations",
        json={
            "prompt": "test",
            "size": "1024x1024",
            # model field omitted
        },
    )
    assert response.status_code == 200


def test_generate_images_rejects_model_mismatch(test_client):
    response = test_client.post(
        "/v1/images/generations",
        json={
            "prompt": "test",
            "model": "Qwen/Qwen-Image-2512",
            "size": "1024x1024",
        },
    )
    assert response.status_code == 400
    assert "model mismatch" in response.json()["detail"].lower()


@pytest.mark.parametrize(
    ("output_format", "expected_pil_format"),
    [("png", "PNG"), ("jpeg", "JPEG"), ("webp", "WEBP")],
)
def test_image_file_response_format_multiple(test_client, output_format, expected_pil_format):
    """Test response_format=file with n>1 returns ZIP archive"""
    response = test_client.post(
        "/v1/images/generations",
        json={
            "prompt": "a dog",
            "n": 3,
            "response_format": "file",
            "output_format": output_format,
        },
    )

    assert response.status_code == 200
    assert response.headers["content-type"] == "application/zip"
    assert "attachment" in response.headers.get("content-disposition", "")
    assert ".zip" in response.headers.get("content-disposition", "")

    # Verify it's a valid ZIP with 3 correctly labelled image files
    import zipfile

    zip_buffer = io.BytesIO(response.content)
    with zipfile.ZipFile(zip_buffer, "r") as zf:
        files = zf.namelist()
        assert len(files) == 3
        assert all(f.endswith(f".{output_format}") for f in files)

        # Verify each file's bytes match its advertised format
        for filename in files:
            img_bytes = zf.read(filename)
            img = Image.open(io.BytesIO(img_bytes))
            assert img.format == expected_pil_format


@pytest.mark.parametrize(
    ("output_format", "expected_media_type", "expected_pil_format"),
    [
        ("png", "image/png", "PNG"),
        ("jpg", "image/jpeg", "JPEG"),
        ("jpeg", "image/jpeg", "JPEG"),
        ("webp", "image/webp", "WEBP"),
    ],
)
def test_image_file_response_format_single(test_client, output_format, expected_media_type, expected_pil_format):
    """Test response_format=file with n=1 returns a single image file."""
    response = test_client.post(
        "/v1/images/generations",
        json={
            "prompt": "a dog",
            "n": 1,
            "response_format": "file",
            "output_format": output_format,
        },
    )

    assert response.status_code == 200
    assert response.headers["content-type"] == expected_media_type
    assert "attachment" in response.headers.get("content-disposition", "")
    assert f".{output_format}" in response.headers.get("content-disposition", "")

    img = Image.open(io.BytesIO(response.content))
    assert img.format == expected_pil_format


@pytest.mark.parametrize(
    ("output_format", "image_count", "expected_media_type", "expected_pil_format"),
    [
        ("jpeg", 1, "image/jpeg", "JPEG"),
        ("webp", 2, "application/zip", "WEBP"),
    ],
)
def test_multistage_image_file_response_uses_requested_format(
    async_omni_test_client,
    output_format,
    image_count,
    expected_media_type,
    expected_pil_format,
):
    engine = async_omni_test_client.app.state.engine_client
    engine._images = [Image.new("RGB", (16, 16), color="green") for _ in range(image_count)]

    response = async_omni_test_client.post(
        "/v1/images/generations",
        json={
            "prompt": "a dog",
            "n": image_count,
            "response_format": "file",
            "output_format": output_format,
        },
    )

    assert response.status_code == 200
    assert response.headers["content-type"] == expected_media_type
    if image_count == 1:
        assert f".{output_format}" in response.headers["content-disposition"]
        assert Image.open(io.BytesIO(response.content)).format == expected_pil_format
        return

    import zipfile

    with zipfile.ZipFile(io.BytesIO(response.content), "r") as archive:
        filenames = archive.namelist()
        assert len(filenames) == image_count
        assert all(filename.endswith(f".{output_format}") for filename in filenames)
        for filename in filenames:
            assert Image.open(io.BytesIO(archive.read(filename))).format == expected_pil_format


def make_test_image_bytes(size=(64, 64)) -> bytes:
    img = Image.new(
        "RGB",
        size,
    )
    buf = io.BytesIO()
    img.save(buf, format="PNG")
    return buf.getvalue()


def test_image_edit_images_processing(async_omni_test_client):
    img_bytes_1 = make_test_image_bytes((16, 16))
    img_bytes_2 = make_test_image_bytes((32, 32))

    # uploadfile with image key
    response = async_omni_test_client.post(
        "/v1/images/edits",
        files=[
            ("image", img_bytes_1),
            ("image", img_bytes_2),
        ],
        data={"prompt": "hello world."},
    )
    assert response.status_code == 200
    engine = async_omni_test_client.app.state.engine_client
    captured_prompt = engine.captured_prompt
    processed_images = captured_prompt["multi_modal_data"]["image"]
    assert len(processed_images) == 2
    assert isinstance(processed_images[0], Image.Image)
    assert isinstance(processed_images[1], Image.Image)
    assert processed_images[0].size == (16, 16)
    assert processed_images[1].size == (32, 32)

    # uploadfile with image[] key
    response = async_omni_test_client.post(
        "/v1/images/edits",
        files=[
            ("image[]", img_bytes_2),
            ("image[]", img_bytes_1),
        ],
        data={"prompt": "hello world."},
    )

    assert response.status_code == 200
    engine = async_omni_test_client.app.state.engine_client
    captured_prompt = engine.captured_prompt
    processed_images = captured_prompt["multi_modal_data"]["image"]
    assert len(processed_images) == 2
    assert isinstance(processed_images[0], Image.Image)
    assert isinstance(processed_images[1], Image.Image)
    assert processed_images[0].size == (32, 32)
    assert processed_images[1].size == (16, 16)

    # base64 url
    buf1 = io.BytesIO()
    img1 = Image.new("RGB", (16, 16))
    img1.save(buf1, format="PNG")
    b64_1 = "data:image/png;base64," + base64.b64encode(buf1.getvalue()).decode()

    buf2 = io.BytesIO()
    img2 = Image.new("RGB", (24, 24))
    img2.save(buf2, format="PNG")
    b64_2 = "data:image/png;base64," + base64.b64encode(buf2.getvalue()).decode()

    response = async_omni_test_client.post(
        "/v1/images/edits",
        data={
            "prompt": "hello from base64",
            "url": [b64_1, b64_2],
        },
    )
    assert response.status_code == 200
    processed_images = engine.captured_prompt["multi_modal_data"]["image"]
    assert len(processed_images) == 2
    assert isinstance(processed_images[0], Image.Image)
    assert isinstance(processed_images[1], Image.Image)
    assert processed_images[0].size == (16, 16)
    assert processed_images[1].size == (24, 24)


def test_image_edit_rejects_multiple_images_when_model_does_not_support_them(async_omni_test_client):
    img_bytes_1 = make_test_image_bytes((16, 16))
    img_bytes_2 = make_test_image_bytes((32, 32))

    engine = async_omni_test_client.app.state.engine_client
    engine.get_diffusion_od_config = lambda: SimpleNamespace(supports_multimodal_inputs=False)

    response = async_omni_test_client.post(
        "/v1/images/edits",
        files=[
            ("image", img_bytes_1),
            ("image", img_bytes_2),
        ],
        data={"prompt": "hello world."},
    )

    assert response.status_code == 400
    assert (
        response.json()["detail"] == "Received multiple input images. Only a single image is supported by this model."
    )
    assert engine.captured_prompt is None


def test_image_edit_rejects_model_mismatch(test_client):
    img_bytes = make_test_image_bytes((16, 16))
    response = test_client.post(
        "/v1/images/edits",
        files=[("image", img_bytes)],
        data={
            "prompt": "edit me",
            "model": "Qwen/Qwen-Image-Edit",
        },
    )
    assert response.status_code == 400
    assert "model mismatch" in response.json()["detail"].lower()


def test_image_edit_rejects_too_many_images_for_qwen_image_edit_2511(async_omni_test_client):
    engine = async_omni_test_client.app.state.engine_client
    engine.get_diffusion_od_config = lambda: SimpleNamespace(
        supports_multimodal_inputs=True,
        max_multimodal_image_inputs=4,
    )

    response = async_omni_test_client.post(
        "/v1/images/edits",
        files=[
            ("image", make_test_image_bytes((16, 16))),
            ("image", make_test_image_bytes((16, 16))),
            ("image", make_test_image_bytes((16, 16))),
            ("image", make_test_image_bytes((16, 16))),
            ("image", make_test_image_bytes((16, 16))),
        ],
        data={"prompt": "hello world."},
    )

    assert response.status_code == 400
    assert response.json()["detail"] == "Received 5 input images. At most 4 images are supported by this model."
    assert engine.captured_prompt is None


def test_image_edit_rejects_too_many_images_for_qwen_image_edit_2511_before_loading(
    async_omni_test_client, monkeypatch: pytest.MonkeyPatch
):
    import vllm_omni.entrypoints.openai.api_server as api_server_module

    engine = async_omni_test_client.app.state.engine_client
    engine.get_diffusion_od_config = lambda: SimpleNamespace(
        supports_multimodal_inputs=True,
        max_multimodal_image_inputs=4,
    )

    def _fail_load(*args, **kwargs):
        raise AssertionError("_load_input_images should not run for over-limit requests")

    monkeypatch.setattr(api_server_module, "_load_input_images", _fail_load)

    response = async_omni_test_client.post(
        "/v1/images/edits",
        files=[
            ("image", make_test_image_bytes((16, 16))),
            ("image", make_test_image_bytes((16, 16))),
            ("image", make_test_image_bytes((16, 16))),
            ("image", make_test_image_bytes((16, 16))),
            ("image", make_test_image_bytes((16, 16))),
        ],
        data={"prompt": "hello world."},
    )

    assert response.status_code == 400
    assert response.json()["detail"] == "Received 5 input images. At most 4 images are supported by this model."
    assert engine.captured_prompt is None


def test_image_edit_ignores_mock_like_multimodal_limit(async_omni_test_client):
    engine = async_omni_test_client.app.state.engine_client
    engine.get_diffusion_od_config = lambda: SimpleNamespace(
        supports_multimodal_inputs=SimpleNamespace(),
        max_multimodal_image_inputs=SimpleNamespace(),
    )

    response = async_omni_test_client.post(
        "/v1/images/edits",
        files=[("image", make_test_image_bytes((16, 16)))],
        data={"prompt": "hello world."},
    )

    assert response.status_code == 200
    captured_prompt = engine.captured_prompt
    assert captured_prompt is not None
    # Multi-stage path uses "img2img" key for single reference image
    processed_images = captured_prompt["multi_modal_data"]["img2img"]
    assert isinstance(processed_images, Image.Image)
    assert processed_images.size == (16, 16)


def test_image_edit_parameter_pass(async_omni_test_client):
    img_bytes_1 = make_test_image_bytes((16, 16))

    # uploadfile with image key
    response = async_omni_test_client.post(
        "/v1/images/edits",
        files=[("image", img_bytes_1)],
        data={
            "prompt": "hello world.",
            "size": "16x24",
            "output_format": "jpeg",
            "num_inference_steps": 20,
            "guidance_scale": 8.0,
            "guidance_scale_2": 2.0,
            "seed": 1234,
            "negative_prompt": "negative",
            "n": 2,
        },
    )
    assert response.status_code == 200
    engine = async_omni_test_client.app.state.engine_client
    captured_prompt = engine.captured_prompt
    captured_sampling_params = engine.captured_sampling_params_list[-1]

    assert captured_prompt["prompt"] == "hello world."
    assert captured_prompt["negative_prompt"] == "negative"
    assert captured_sampling_params.num_inference_steps == 20
    assert captured_sampling_params.guidance_scale == 8.0
    assert captured_sampling_params.guidance_scale_2 == 2.0
    assert captured_sampling_params.seed == 1234
    assert captured_sampling_params.num_outputs_per_prompt == 2
    assert captured_sampling_params.width == 16
    assert captured_sampling_params.height == 24

    data = response.json()
    # All images should be valid
    for img_data in data["data"]:
        assert "b64_json" in img_data
        img_bytes = base64.b64decode(img_data["b64_json"])
        img = Image.open(io.BytesIO(img_bytes))
        assert img.format.lower() == "jpeg"
        assert data["output_format"] == "jpeg"
        assert data["size"] == "64x64"


def test_image_edit_layers_and_resolution(async_omni_test_client):
    """Test layers and resolution parameters for layered models."""
    img_bytes = make_test_image_bytes((16, 16))

    response = async_omni_test_client.post(
        "/v1/images/edits",
        files=[("image", img_bytes)],
        data={
            "prompt": "decompose into layers",
            "layers": 4,
            "resolution": 1024,
        },
    )
    assert response.status_code == 200
    engine = async_omni_test_client.app.state.engine_client
    captured_sampling_params = engine.captured_sampling_params_list[-1]
    assert captured_sampling_params.layers == 4
    assert captured_sampling_params.resolution == 1024


def test_image_edit_resolution_auto_size(async_omni_test_client):
    """Test that size='auto' with resolution lets pipeline calculate dimensions."""
    img_bytes = make_test_image_bytes((16, 16))

    response = async_omni_test_client.post(
        "/v1/images/edits",
        files=[("image", img_bytes)],
        data={
            "prompt": "test",
            "size": "auto",
            "resolution": 640,
        },
    )
    assert response.status_code == 200
    engine = async_omni_test_client.app.state.engine_client
    captured_sampling_params = engine.captured_sampling_params_list[-1]
    # When resolution is set with size=auto, width/height should be None
    # to let pipeline calculate based on resolution
    assert captured_sampling_params.width is None
    assert captured_sampling_params.height is None
    assert captured_sampling_params.resolution == 640


def test_image_edit_invalid_resolution(async_omni_test_client):
    """Test that invalid resolution values are rejected with 400."""
    img_bytes = make_test_image_bytes((16, 16))

    response = async_omni_test_client.post(
        "/v1/images/edits",
        files=[("image", img_bytes)],
        data={
            "prompt": "test",
            "resolution": 512,  # Invalid, only 640 or 1024 are supported
        },
    )
    assert response.status_code == 400
    detail = response.json()["detail"]
    assert "Invalid resolution" in detail
    assert "512" in detail


def test_image_edit_invalid_layers(async_omni_test_client):
    """Test that layered image edits reject out-of-range layers with 400."""
    img_bytes = make_test_image_bytes((16, 16))

    # Test layers below the supported range
    response = async_omni_test_client.post(
        "/v1/images/edits",
        files=[("image", img_bytes)],
        data={
            "prompt": "test",
            "layers": 1,
        },
    )
    assert response.status_code == 400
    detail = response.json()["detail"]
    assert "Invalid layers" in detail
    assert "layers must be between 2 and 10 inclusive" in detail

    # Test layers above the supported range
    response = async_omni_test_client.post(
        "/v1/images/edits",
        files=[("image", img_bytes)],
        data={
            "prompt": "test",
            "layers": 11,
        },
    )
    assert response.status_code == 400
    detail = response.json()["detail"]
    assert "Invalid layers" in detail
    assert "layers must be between 2 and 10 inclusive" in detail


def test_image_edit_resolution_and_size_conflict(async_omni_test_client):
    """Test that providing both resolution and explicit size raises 400."""
    img_bytes = make_test_image_bytes((16, 16))

    response = async_omni_test_client.post(
        "/v1/images/edits",
        files=[("image", img_bytes)],
        data={
            "prompt": "test",
            "resolution": 1024,
            "size": "512x512",  # Conflict: both resolution and explicit size
        },
    )
    assert response.status_code == 400
    detail = response.json()["detail"]
    assert "Cannot specify both" in detail
    assert "resolution" in detail
    assert "size" in detail


def test_image_edit_parameter_default(async_omni_test_client):
    img_bytes_1 = make_test_image_bytes((24, 16))

    # uploadfile with image key
    response = async_omni_test_client.post(
        "/v1/images/edits",
        files=[("image", img_bytes_1)],
        data={
            "prompt": "hello world.",
            "size": "auto",
        },
    )
    assert response.status_code == 200
    engine = async_omni_test_client.app.state.engine_client
    captured_sampling_params = engine.captured_sampling_params_list[-1]

    # size="auto" on multi-stage pipelines deliberately leaves the diffusion
    # stages sampling_params width/height unset so AR-driven pipelines (e.g.
    # HunyuanImage-3.0) can let ar2diffusion override the final bucket from
    # the AR-predicted ratio token; see
    # test_image_edits_size_auto_preserves_bridge_size for the contract.
    # Single-stage diffusion (test_image_edit_parameter_default_single_stage)
    # still pins width/height to the input image size via api_servers
    # gen_params, which is unchanged.
    assert captured_sampling_params.width is None
    assert captured_sampling_params.height is None
    assert captured_sampling_params.num_outputs_per_prompt == 1
    assert captured_sampling_params.num_inference_steps == 4
    assert captured_sampling_params.guidance_scale == 7.5
    assert captured_sampling_params.generator_device == "cpu"

    # Test that a size exceeding max_generated_image_size returns 400
    response = async_omni_test_client.post(
        "/v1/images/edits",
        files=[("image", img_bytes_1)],
        data={
            "prompt": "hello world.",
            "size": "2048x2048",  # 4,194,304 pixels > max_generated_image_size (1,048,576)
        },
    )
    assert response.status_code == 400


def test_image_edit_parameter_default_single_stage(test_client):
    img_bytes_1 = make_test_image_bytes((24, 16))

    # uploadfile with image key
    response = test_client.post(
        "/v1/images/edits",
        files=[("image", img_bytes_1)],
        data={
            "prompt": "hello world.",
        },
    )
    assert response.status_code == 200
    engine = test_client.app.state.engine_client
    captured_sampling_params = engine.captured_sampling_params_list[0]

    assert captured_sampling_params.width == 24
    assert captured_sampling_params.height == 16
    assert (captured_sampling_params.height_not_provided, captured_sampling_params.width_not_provided) == (True, True)
    assert captured_sampling_params.num_outputs_per_prompt == 1
    assert captured_sampling_params.num_inference_steps == 4
    assert captured_sampling_params.guidance_scale == 7.5
    assert captured_sampling_params.generator_device == "cpu"

    # Size exceeding max_generated_image_size (1024*1792) returns 400
    response = test_client.post(
        "/v1/images/edits",
        files=[("image", img_bytes_1)],
        data={
            "prompt": "hello world.",
            "size": "2048x2048",
        },
    )
    assert response.status_code == 400


def test_image_edit_explicit_size_marks_canvas_provided_single_stage(test_client):
    response = test_client.post(
        "/v1/images/edits",
        files=[("image", make_test_image_bytes((24, 16)))],
        data={"prompt": "hello world.", "size": "16x24"},
    )

    assert response.status_code == 200
    sampling = test_client.app.state.engine_client.captured_sampling_params_list[0]
    assert (sampling.height, sampling.width) == (24, 16)
    assert (sampling.height_not_provided, sampling.width_not_provided) == (False, False)


def test_image_edit_response_size_reports_generated_image_single_stage(test_client):
    response = test_client.post(
        "/v1/images/edits",
        files=[("image", make_test_image_bytes((24, 16)))],
        data={"prompt": "hello world.", "size": "16x24"},
    )

    assert response.status_code == 200
    assert response.json()["size"] == "64x64"


def test_generate_images_response_size_reports_generated_image(test_client):
    response = test_client.post(
        "/v1/images/generations",
        json={"prompt": "a cat", "n": 1, "size": "1024x1024"},
    )

    assert response.status_code == 200
    assert response.json()["size"] == "64x64"


def test_image_edit_compression_jpeg(test_client):
    img_bytes_1 = make_test_image_bytes((16, 16))
    # uploadfile with image key
    response = test_client.post(
        "/v1/images/edits",
        files=[("image", img_bytes_1)],
        data={"prompt": "hello world.", "output_format": "jpeg", "output_compression": 100},
    )
    assert response.status_code == 200
    data = response.json()
    img_bytes_100 = base64.b64decode(data["data"][0]["b64_json"])
    img = Image.open(io.BytesIO(img_bytes_100))
    assert img.format.lower() == "jpeg"

    response = test_client.post(
        "/v1/images/edits",
        files=[("image", img_bytes_1)],
        data={
            "prompt": "hello world.",
            "output_format": "jpeg",
            "output_compression": 50,
        },
    )
    assert response.status_code == 200
    data = response.json()
    img_bytes_50 = base64.b64decode(data["data"][0]["b64_json"])

    response = test_client.post(
        "/v1/images/edits",
        files=[("image", img_bytes_1)],
        data={
            "prompt": "hello world.",
            "output_format": "jpeg",
            "output_compression": 10,
        },
    )
    assert response.status_code == 200
    data = response.json()
    img_bytes_10 = base64.b64decode(data["data"][0]["b64_json"])

    assert len(img_bytes_10) < len(img_bytes_50)
    assert len(img_bytes_50) < len(img_bytes_100)


def test_image_edit_rgba_output_converts_to_jpeg(async_omni_rgba_test_client):
    img_bytes_1 = make_test_image_bytes((16, 16))

    response = async_omni_rgba_test_client.post(
        "/v1/images/edits",
        files=[("image", img_bytes_1)],
        data={
            "prompt": "hello world.",
            "output_format": "jpeg",
        },
    )
    assert response.status_code == 200

    data = response.json()
    img_bytes = base64.b64decode(data["data"][0]["b64_json"])
    img = Image.open(io.BytesIO(img_bytes))
    assert img.format.lower() == "jpeg"
    assert img.mode == "RGB"
    assert data["output_format"] == "jpeg"


def test_image_edit_compression_png(async_omni_test_client):
    img_bytes_1 = make_test_image_bytes((16, 16))
    # uploadfile with image key
    response = async_omni_test_client.post(
        "/v1/images/edits",
        files=[("image", img_bytes_1)],
        data={"prompt": "hello world.", "output_format": "PNG", "output_compression": 100},
    )
    assert response.status_code == 200
    data = response.json()
    img_bytes_100 = base64.b64decode(data["data"][0]["b64_json"])
    img = Image.open(io.BytesIO(img_bytes_100))
    assert img.format.lower() == "png"

    response = async_omni_test_client.post(
        "/v1/images/edits",
        files=[("image", img_bytes_1)],
        data={
            "prompt": "hello world.",
            "output_format": "PNG",
            "output_compression": 50,
        },
    )
    assert response.status_code == 200
    data = response.json()
    img_bytes_50 = base64.b64decode(data["data"][0]["b64_json"])

    response = async_omni_test_client.post(
        "/v1/images/edits",
        files=[("image", img_bytes_1)],
        data={
            "prompt": "hello world.",
            "output_format": "PNG",
            "output_compression": 10,
        },
    )
    assert response.status_code == 200
    data = response.json()
    img_bytes_10 = base64.b64decode(data["data"][0]["b64_json"])

    assert len(img_bytes_10) < len(img_bytes_50)
    assert len(img_bytes_50) < len(img_bytes_100)


def test_image_edit_with_seed_zero(async_omni_test_client):
    """Test that seed=0 is correctly handled in image editing.

    Previously, seed=0 was incorrectly replaced by a random seed due to the
    falsy value check using `or` operator. This test ensures seed=0 is
    properly passed through to the sampling parameters in image editing.
    """
    img_bytes_1 = make_test_image_bytes((16, 16))

    response = async_omni_test_client.post(
        "/v1/images/edits",
        files=[("image", img_bytes_1)],
        data={
            "prompt": "edit this image",
            "seed": 0,
        },
    )
    assert response.status_code == 200
    engine = async_omni_test_client.app.state.engine_client
    captured_sampling_params = engine.captured_sampling_params_list[-1]
    # Verify that seed=0 is correctly passed
    assert captured_sampling_params.seed == 0, (
        f"Expected seed=0, but got seed={captured_sampling_params.seed}. "
        "This indicates the bug where seed=0 is treated as falsy."
    )


def test_image_edits_returns_metrics_single_stage(test_client):
    """Single-stage /v1/images/edits copies getattr metrics onto the response."""
    stage_durations = {"queue_wait_ms": 1.0, "stage_0_gen_ms": 2.0}
    peak_memory_mb = 1024.0
    _stub_engine_generate_with_metrics(
        test_client.app.state.engine_client,
        stage_durations=stage_durations,
        peak_memory_mb=peak_memory_mb,
    )

    response = test_client.post(
        "/v1/images/edits",
        files=[("image", make_test_image_bytes((16, 16)))],
        data={"prompt": "edit me"},
    )
    assert response.status_code == 200
    assert response.json()["metrics"] == {
        "stage_durations": stage_durations,
        "peak_memory_mb": peak_memory_mb,
    }


def test_image_edits_returns_metrics_multistage(async_omni_test_client):
    """Multi-stage /v1/images/edits unpacks generate_diffusion_images metrics."""
    stage_durations = {
        "queue_wait_ms": 1.0,
        "preprocess_ms": 2.0,
        "ar2diffusion_ms": 3.0,
        "stage_0_gen_ms": 4.0,
        "stage_1_gen_ms": 5.0,
    }
    peak_memory_mb = 2048.0
    _stub_engine_generate_with_metrics(
        async_omni_test_client.app.state.engine_client,
        stage_durations=stage_durations,
        peak_memory_mb=peak_memory_mb,
    )

    response = async_omni_test_client.post(
        "/v1/images/edits",
        files=[("image", make_test_image_bytes((16, 16)))],
        data={"prompt": "edit me"},
    )
    assert response.status_code == 200
    assert response.json()["metrics"] == {
        "stage_durations": stage_durations,
        "peak_memory_mb": peak_memory_mb,
    }


def test_image_edit_with_seed_zero_single_stage(test_client):
    """Test that seed=0 is correctly handled in image editing (single stage).

    Test seed=0 handling in image editing with single stage path.
    """
    img_bytes_1 = make_test_image_bytes((16, 16))

    response = test_client.post(
        "/v1/images/edits",
        files=[("image", img_bytes_1)],
        data={
            "prompt": "edit this image",
            "seed": 0,
        },
    )
    assert response.status_code == 200
    engine = test_client.app.state.engine_client
    captured_sampling_params = engine.captured_sampling_params_list[0]
    # Verify that seed=0 is correctly passed
    assert captured_sampling_params.seed == 0, (
        f"Expected seed=0, but got seed={captured_sampling_params.seed}. "
        "This indicates the bug where seed=0 is treated as falsy."
    )


def test_normalize_image():
    """Test _normalize_image with various input types"""
    import numpy as np

    from vllm_omni.entrypoints.openai.images.helpers import _normalize_image

    # Test PIL Image input
    img = Image.new("RGB", (64, 64), color="red")
    result = _normalize_image(img)
    assert isinstance(result, Image.Image)
    assert result.size == (64, 64)

    # Test uint8 numpy array
    arr = np.random.randint(0, 255, (64, 64, 3), dtype=np.uint8)
    result = _normalize_image(arr)
    assert isinstance(result, Image.Image)
    assert result.size == (64, 64)

    # Test float [0, 1] numpy array
    arr = np.random.rand(64, 64, 3).astype(np.float32)
    result = _normalize_image(arr)
    assert isinstance(result, Image.Image)
    assert result.size == (64, 64)

    # Test float [-1, 1] numpy array
    arr = np.random.rand(64, 64, 3).astype(np.float32) * 2 - 1
    result = _normalize_image(arr)
    assert isinstance(result, Image.Image)
    assert result.size == (64, 64)

    # Test batch dimensions (1, 1, H, W, C)
    arr = np.random.randint(0, 255, (1, 1, 64, 64, 3), dtype=np.uint8)
    result = _normalize_image(arr)
    assert isinstance(result, Image.Image)
    assert result.size == (64, 64)


def test_extract_images_from_result():
    """Test _extract_images_from_result with various result formats"""
    import numpy as np

    from vllm_omni.entrypoints.openai.images.helpers import _extract_images_from_result

    # Test empty result
    class EmptyResult:
        pass

    result = EmptyResult()
    images = _extract_images_from_result(result)
    assert images == []

    # Test nested batch: [np.array(shape=(3, 64, 64, 3))]
    batch = np.random.randint(0, 255, (3, 1, 64, 64, 3), dtype=np.uint8)

    class BatchResult:
        def __init__(self):
            self.images = [batch]

    result = BatchResult()
    images = _extract_images_from_result(result)
    assert len(images) == 3
    assert all(isinstance(img, Image.Image) for img in images)
    assert all(img.size == (64, 64) for img in images)

    # Test result with "images" attribute set in __init__
    class DictRequestOutput:
        def __init__(self):
            self.images = [np.random.randint(0, 255, (64, 64, 3), dtype=np.uint8)]

    result = DictRequestOutput()
    images = _extract_images_from_result(result)
    assert len(images) == 1
    assert isinstance(images[0], Image.Image)

    # Test result with "images" attribute from an inner object
    class AttrRequestOutput:
        def __init__(self):
            self.images = [np.random.randint(0, 255, (32, 32, 3), dtype=np.uint8)]

    result = AttrRequestOutput()
    images = _extract_images_from_result(result)
    assert len(images) == 1
    assert isinstance(images[0], Image.Image)
    assert images[0].size == (32, 32)


# ---------------------------------------------------------------------------
# _check_max_generated_image_size unit tests
# ---------------------------------------------------------------------------


def test_width_height_within_limit_passes():
    args = SimpleNamespace(max_generated_image_size=1024 * 1024)
    # Exactly at limit is allowed (> not >=)
    _check_max_generated_image_size(args, 1024, 1024)
    # Below limit
    _check_max_generated_image_size(args, 512, 512)


def test_width_height_exceeds_limit_raises_400():
    limit = 1024 * 1024
    args = SimpleNamespace(max_generated_image_size=limit)
    with pytest.raises(HTTPException) as exc_info:
        _check_max_generated_image_size(args, 1025, 1024)
    assert exc_info.value.status_code == HTTPStatus.BAD_REQUEST.value
    assert "1025x1024" in exc_info.value.detail
    assert str(limit) in exc_info.value.detail


def test_width_height_error_message_contains_size_hint():
    args = SimpleNamespace(max_generated_image_size=512 * 512)
    with pytest.raises(HTTPException) as exc_info:
        _check_max_generated_image_size(args, 1024, 512)
    assert "--max-generated-image-size" in exc_info.value.detail


def test_resolution_within_limit_passes():
    args = SimpleNamespace(max_generated_image_size=1024 * 1024)
    # Exactly at limit is allowed (> not >=): 1024*1024 == limit
    _check_max_generated_image_size(args, None, None, resolution=1024)
    # Below limit
    _check_max_generated_image_size(args, None, None, resolution=512)


def test_resolution_exceeds_limit_raises_400():
    limit = 1024 * 1024
    args = SimpleNamespace(max_generated_image_size=limit)
    with pytest.raises(HTTPException) as exc_info:
        _check_max_generated_image_size(args, None, None, resolution=1025)
    assert exc_info.value.status_code == HTTPStatus.BAD_REQUEST.value
    detail = exc_info.value.detail
    assert "1025" in detail
    assert "1025x1025" in detail
    assert str(limit) in detail


def test_image_edits_size_auto_preserves_bridge_size(async_omni_stage_configs_only_client):
    """size=auto must NOT pin the diffusion stage sampling_params.height/width.

    Regression: prior to the fix, edit_images resolved size=auto to the
    first input image dimensions and forwarded them through gen_params +
    extra_body to the diffusion stages sampling_params. AR-driven
    pipelines (e.g. HunyuanImage-3.0) rely on ar2diffusions
    bridge to override the final bucket via the AR-predicted ratio token,
    and the DiT pre_process_func only fills sampling_params from the
    bridge value when sampling_params.width is None (see
    pipeline_hunyuan_image3.py:290). Non-None width from the input image
    silently suppressed the AR decision, producing the wrong bucket
    (e.g. 1024x1024 square instead of the AR-decided 1280x720 landscape
    for multi-image fusion).

    Cross-pins the multi-image fix at the API level: 2 reference images
    with bot_task=think must produce 2 <img> placeholders in the captured
    AR prompt (build_prompt called with num_images=2).
    """
    img_a = make_test_image_bytes((32, 32))
    img_b = make_test_image_bytes((128, 64))
    response = async_omni_stage_configs_only_client.post(
        "/v1/images/edits",
        files=[("image", img_a), ("image", img_b)],
        data={
            "prompt": "fuse",
            "size": "auto",
            "bot_task": "think",
        },
    )
    assert response.status_code == 200, response.text

    engine = async_omni_stage_configs_only_client.app.state.engine_client
    captured = engine.captured_sampling_params_list
    assert captured is not None
    assert len(captured) == 2

    diffusion_params = captured[1]
    assert diffusion_params.height is None, (
        f"size=auto leaked into diffusion sampling_params.height={diffusion_params.height}; "
        "must stay None so AR-driven pipelines can apply the bridges decision."
    )
    assert diffusion_params.width is None, (
        f"size=auto leaked into diffusion sampling_params.width={diffusion_params.width}; "
        "must stay None so AR-driven pipelines can apply the bridges decision."
    )

    KEY = "prompt"
    IMG = "<img>"
    captured_prompt = engine.captured_prompt
    if isinstance(captured_prompt, dict) and isinstance(captured_prompt.get("prompt"), str):
        assert captured_prompt["prompt"].count("<img>") == 2, (
            f"N=2 reference images must emit 2 <img> placeholders in AR prompt; got {captured_prompt[KEY].count(IMG)} -- prompt: {captured_prompt[KEY]!r}"
        )


@pytest.mark.xfail(
    strict=True,
    reason=(
        "Pre-existing gap, not introduced by this change: the /v1/images/edits route in "
        "api_server.py never calls resolve_stop_token_ids at all (grep: api_server.py has "
        "no stop_token_ids reference), so the AR stage keeps SamplingParams' default empty "
        "list. The omitted-bot_task fix landed in serving_chat.py, which is the only "
        "production caller; that path is covered by "
        "test_serving_chat_multistage_generation.py::"
        "test_build_multistage_generation_inputs_omitted_bot_task_matches_prompt_default. "
        "Wiring the images/edits route through the same seam needs a tokenizer in that "
        "scope and a decision on whether HunyuanImage3 it2i should resolve AR stop tokens "
        "unconditionally (today the whole AR block is gated on an explicit bot_task / "
        "use_system_prompt / system_prompt), so it is tracked separately."
    ),
)
def test_image_edits_omitted_bot_task_stop_tokens_match_prompt_default(
    async_omni_stage_configs_only_client,
):
    """Regression: an omitted bot_task must resolve identically for the AR
    prompt and its stop_token_ids.

    build_prompt/build_prompt_tokens default an omitted bot_task per-task
    (e.g. "think" for the base "it2i" task, since it isn't itself a key in
    _TASK_PRESETS). resolve_stop_token_ids must land on that same default
    to compute the matching stop set. Passing the raw (still-None) outer
    bot_task variable to resolve_stop_token_ids -- instead of mirroring
    build_kwargs's own omitted-or-not "bot_task" entry -- made it normalize
    bot_task=None instead of "think", so it fell through to the full
    <img_ratio_*> stop range instead of the think/recaption-only pair.

    An explicit (non-"auto") size is required to reach this: with
    need_ratio=True (size="auto"), resolve_stop_token_ids returns the full
    ratio range regardless of bot_task, so the two code paths only visibly
    disagree once a concrete size selects the narrower think/recaption stop
    set.
    """
    from vllm_omni.diffusion.models.hunyuan_image3.prompt_utils import (
        HUNYUAN_IMAGE3_SPECIAL_TOKEN_IDS,
    )

    img = make_test_image_bytes((64, 64))
    response = async_omni_stage_configs_only_client.post(
        "/v1/images/edits",
        files=[("image", img)],
        data={
            "prompt": "make it neon",
            "size": "512x512",
        },
    )
    assert response.status_code == 200, response.text

    engine = async_omni_stage_configs_only_client.app.state.engine_client
    captured = engine.captured_sampling_params_list
    assert captured is not None

    ar_params = captured[0]
    expected_stop_token_ids = [
        HUNYUAN_IMAGE3_SPECIAL_TOKEN_IDS["</think>"],
        HUNYUAN_IMAGE3_SPECIAL_TOKEN_IDS["</recaption>"],
    ]
    assert ar_params.stop_token_ids == expected_stop_token_ids, (
        f"omitted bot_task with an explicit size must resolve stop_token_ids "
        f"for the default 'think' bot_task ({expected_stop_token_ids}); got "
        f"{ar_params.stop_token_ids} -- this is the full ratio range, meaning "
        "resolve_stop_token_ids disagreed with build_prompt_tokens's default."
    )