[Test] Add image-to-video offline example docs and tests (#3573)

Signed-off-by: loveysuby <loveysuby@users.noreply.github.com>
Signed-off-by: Hyoseop Song <crad_on25@naver.com>
Signed-off-by: Didan Deng <33117903+wtomin@users.noreply.github.com>
Co-authored-by: loveysuby <loveysuby@users.noreply.github.com>
Co-authored-by: Didan Deng <33117903+wtomin@users.noreply.github.com>

tests/examples/offline_inference/test_image_to_video.py

@@ -0,0 +1,81 @@
+"""
+Offline inference tests: image-to-video.
+See examples/offline_inference/image_to_video/README.md
+"""
+
+import shutil
+from pathlib import Path
+
+import pytest
+import requests
+
+from tests.examples.helpers import EXAMPLES, ExampleRunner, ReadmeSnippet
+from tests.helpers.assertions import assert_video_valid
+from tests.helpers.mark import hardware_marks
+
+pytestmark = [
+    pytest.mark.usefixtures("clean_gpu_memory_between_tests"),
+    pytest.mark.full_model,
+    pytest.mark.example,
+    *hardware_marks(res={"cuda": "H100"}),
+]
+
+I2V_SCRIPT = EXAMPLES / "offline_inference" / "image_to_video" / "image_to_video.py"
+README_PATH = I2V_SCRIPT.with_name("README.md")
+EXAMPLE_OUTPUT_SUBFOLDER = "example_offline_i2v"
+
+_IMAGE_URL = "https://vllm-public-assets.s3.us-west-2.amazonaws.com/vision_model_images/cherry_blossom.jpg"
+_IMAGE_NAME = "cherry_blossom.jpg"
+
+_SKIP_SECTIONS = {
+    "Prerequisites",
+    "Advanced Features",
+    "FAQ",
+    # VACE conditional tasks are covered by test_vace_video_generation.py, which
+    # runs the same README snippets with synthetic assets and smoke settings. The
+    # prep block here downloads inputs via wget (not portable, not collected), so
+    # exercising this section from the shared runner would only duplicate and fail.
+    "Wan2.1 VACE Conditional Tasks",
+}
+
+
+def _ensure_test_image(run_dir: Path) -> None:
+    """Download or copy the example image into run_dir so CLI snippets can find it."""
+    dest = run_dir / _IMAGE_NAME
+    if dest.exists():
+        return
+    src = I2V_SCRIPT.parent / _IMAGE_NAME
+    if src.exists():
+        shutil.copy2(src, dest)
+        return
+    response = requests.get(_IMAGE_URL, timeout=60)
+    response.raise_for_status()
+    dest.write_bytes(response.content)
+
+
+def _skip_readme_snippet(language: str, code: str, h2_title: str) -> tuple[bool, str]:
+    if h2_title in _SKIP_SECTIONS:
+        return True, f"README section '{h2_title}' is intentionally excluded for examples tests"
+    if language == "python":
+        return True, "Python API snippets produce video files that ExampleRunner does not auto-collect"
+    if "/path/to/" in code:
+        return True, "Snippet references a placeholder local model path"
+    return False, ""
+
+
+README_SNIPPETS = ReadmeSnippet.extract_readme_snippets(README_PATH, skipif=_skip_readme_snippet)
+
+
+@pytest.mark.parametrize("snippet", README_SNIPPETS, ids=lambda snippet: snippet.test_id)
+def test_image_to_video(snippet: ReadmeSnippet, example_runner: ExampleRunner):
+    should_skip, reason = snippet.skip
+    if should_skip:
+        pytest.skip(reason)
+
+    run_dir = example_runner.output_root / EXAMPLE_OUTPUT_SUBFOLDER / snippet.test_id
+    run_dir.mkdir(parents=True, exist_ok=True)
+    _ensure_test_image(run_dir)
+
+    result = example_runner.run(snippet, output_subfolder=Path(EXAMPLE_OUTPUT_SUBFOLDER))
+    for asset in result.assets:
+        assert_video_valid(asset)