[Test] Unify L2/L3 test layout, Buildkite steps, and test helpers (#2556)

Signed-off-by: wangyu <410167048@qq.com>
Signed-off-by: Huang, Zeyu <11222265+fhfuih@users.noreply.github.com>
Signed-off-by: wangyu <53896905+yenuo26@users.noreply.github.com>
Co-authored-by: Huang, Zeyu <11222265+fhfuih@users.noreply.github.com>

tests/e2e/online_serving/test_longcat_image_edit.py

@@ -0,0 +1,69 @@
+"""
+Recommended tests of diffusion features that are available in online serving mode
+and are supported by the following model:
+- LongCat-Image-Edit: image-to-image edit with a single image + single edit prompt input
+Coverage:
+- CPU offloading (model-level sequential offload via --enable-cpu-offload)
+- Cache-DiT
+- SP (Ulysses)
+
+This validates:
+ - Successful image generation at the expected 1024x1024 resolution with recommended feature combinations
+"""
+
+import pytest
+
+from tests.helpers.mark import hardware_marks
+from tests.helpers.media import generate_synthetic_image
+from tests.helpers.runtime import (
+    OmniServer,
+    OmniServerParams,
+    OpenAIClientHandler,
+    dummy_messages_from_mix_data,
+)
+
+EDIT_PROMPT = "Transform this modern image into a cinematic animation style with vibrant colors and soft lighting."
+NEGATIVE_PROMPT = "blurry, low quality, distorted, oversaturated"
+SINGLE_CARD_FEATURE_MARKS = hardware_marks(res={"cuda": "H100"})
+
+
+def _get_diffusion_feature_cases(model: str):
+    """Return diffusion feature cases for LongCat-Image-Edit."""
+    return [
+        pytest.param(
+            OmniServerParams(
+                model=model,
+            ),
+            id="default",
+            marks=SINGLE_CARD_FEATURE_MARKS,
+        )
+    ]
+
+
+@pytest.mark.advanced_model
+@pytest.mark.core_model
+@pytest.mark.diffusion
+@pytest.mark.parametrize(
+    "omni_server",
+    _get_diffusion_feature_cases("meituan-longcat/LongCat-Image-Edit"),
+    indirect=True,
+)
+def test_longcat_image_edit(omni_server: OmniServer, openai_client: OpenAIClientHandler):
+    """Test the recommended feature combinations for LongCat-Image-Edit."""
+    image_data_url = f"data:image/jpeg;base64,{generate_synthetic_image(512, 512)['base64']}"
+    messages = dummy_messages_from_mix_data(image_data_url=image_data_url, content_text=EDIT_PROMPT)
+
+    request_config = {
+        "model": omni_server.model,
+        "messages": messages,
+        "extra_body": {
+            "height": 1024,
+            "width": 1024,
+            "num_inference_steps": 2,
+            "negative_prompt": NEGATIVE_PROMPT,
+            "guidance_scale": 4.0,
+            "seed": 42,
+        },
+    }
+
+    openai_client.send_diffusion_request(request_config)