feat: validate and unblock media downloads

tests/test_media_assets.py

@@ -1,6 +1,11 @@
 from pathlib import Path
 
-from rf4_research.media_assets import extract_media_candidates, merge_manifest, store_asset
+import io
+
+import pytest
+from PIL import Image
+
+from rf4_research.media_assets import extract_media_candidates, inspect_image, merge_manifest, store_asset
 
 
 def test_extracts_and_classifies_unique_https_media() -> None:
@@ -25,6 +30,18 @@ def test_manifest_merges_and_binary_store_is_content_addressed(tmp_path: Path) -
     first = merge_manifest(tmp_path / "manifest.json", [item])
     second = merge_manifest(tmp_path / "manifest.json", [item])
     assert len(first["assets"]) == len(second["assets"]) == 1
-    digest, relative = store_asset(tmp_path, b"image", content_type="image/png", source_url=item.asset_url)
+    image = io.BytesIO()
+    Image.new("RGB", (3, 2), "green").save(image, format="PNG")
+    digest, relative, width, height, mime = store_asset(tmp_path, image.getvalue(), content_type="image/png", source_url=item.asset_url)
     assert len(digest) == 64
-    assert (tmp_path / relative).read_bytes() == b"image"
+    assert (tmp_path / relative).read_bytes() == image.getvalue()
+    assert (width, height, mime) == (3, 2, "image/png")
+
+
+def test_image_inspection_rejects_invalid_body_and_mime_mismatch(tmp_path: Path) -> None:
+    with pytest.raises(ValueError, match="valid raster"):
+        inspect_image(b"not an image")
+    image = io.BytesIO()
+    Image.new("RGB", (1, 1)).save(image, format="PNG")
+    with pytest.raises(ValueError, match="MIME mismatch"):
+        store_asset(tmp_path, image.getvalue(), content_type="image/jpeg", source_url="https://example.test/a.jpg")