[Fix] make images LoRA e2e less flaky (#978)

Signed-off-by: dongbo910220 <1275604947@qq.com>
Co-authored-by: Hongsheng Liu <liuhongsheng4@huawei.com>

.buildkite/pipeline.yml

@@ -41,6 +41,23 @@ steps:
           volumes:
             - "/fsx/hf_cache:/fsx/hf_cache"
 
+  - label: "Diffusion Images API LoRA E2E"
+    timeout_in_minutes: 20
+    depends_on: image-build
+    commands:
+      - pytest -s -v tests/e2e/online_serving/test_images_generations_lora.py
+    agents:
+      queue: "gpu_1_queue" # g6.4xlarge instance on AWS, has 1 L4 GPU
+    plugins:
+      - docker#v5.2.0:
+          image: public.ecr.aws/q9t5s3a7/vllm-ci-test-repo:$BUILDKITE_COMMIT
+          always-pull: true
+          propagate-environment: true
+          environment:
+            - "HF_HOME=/fsx/hf_cache"
+          volumes:
+            - "/fsx/hf_cache:/fsx/hf_cache"
+
   - label: "Diffusion Model CPU offloading Test"
     timeout_in_minutes: 20
     depends_on: image-build

tests/e2e/online_serving/test_images_generations_lora.py

@@ -224,11 +224,11 @@ def test_images_generations_per_request_lora_switching(omni_server: OmniServer,
     base_img = _post_images(omni_server, _basic_payload())
     base_slice = _image_blue_tail_slice(base_img)
 
-    # Adapter A: apply delta to Q slice only.
+    # Adapter A: apply delta to V slice only.
     lora_a_dir = tmp_path / "zimage_lora_a"
-    _write_zimage_lora(lora_a_dir, q_scale=0.1)
+    _write_zimage_lora(lora_a_dir, v_scale=8.0)
     payload_a = _basic_payload()
-    payload_a["lora"] = {"name": "a", "path": str(lora_a_dir), "scale": 2.0}
+    payload_a["lora"] = {"name": "a", "path": str(lora_a_dir), "scale": 64.0}
     img_a = _post_images(omni_server, payload_a)
     a_slice = _image_blue_tail_slice(img_a)
     _assert_slice_diff(a_slice, base_slice, label="lora_a_vs_base")
@@ -236,9 +236,9 @@ def test_images_generations_per_request_lora_switching(omni_server: OmniServer,
 
     # Adapter B: apply delta to K slice only (should differ from adapter A).
     lora_b_dir = tmp_path / "zimage_lora_b"
-    _write_zimage_lora(lora_b_dir, k_scale=0.1)
+    _write_zimage_lora(lora_b_dir, k_scale=4.0)
     payload_b = _basic_payload()
-    payload_b["lora"] = {"name": "b", "path": str(lora_b_dir), "scale": 2.0}
+    payload_b["lora"] = {"name": "b", "path": str(lora_b_dir), "scale": 64.0}
     img_b = _post_images(omni_server, payload_b)
     b_slice = _image_blue_tail_slice(img_b)
     _assert_slice_diff(b_slice, base_slice, label="lora_b_vs_base")