Validate screenshot MIME and filename metadata

apps/api/tests/test_storage.py

@@ -5,7 +5,7 @@ import io
 import pytest
 from PIL import Image
 
-from app.storage import ScreenshotError, prepare_image
+from app.storage import ScreenshotError, prepare_image, validate_upload_metadata
 
 
 def test_prepare_image_removes_metadata() -> None:
@@ -26,3 +26,14 @@ def test_prepare_image_removes_metadata() -> None:
 def test_prepare_image_rejects_non_image() -> None:
     with pytest.raises(ScreenshotError, match="valid image"):
         prepare_image(b"not an image")
+
+
+def test_upload_metadata_requires_matching_supported_mime_and_extension() -> None:
+    validate_upload_metadata("catch.jpeg", "image/jpeg")
+    validate_upload_metadata("catch.webp", "image/webp")
+    with pytest.raises(ScreenshotError, match="extension and MIME"):
+        validate_upload_metadata("catch.exe", "image/jpeg")
+    with pytest.raises(ScreenshotError, match="extension and MIME"):
+        validate_upload_metadata("catch.png", "image/jpeg")
+    with pytest.raises(ScreenshotError, match="extension and MIME"):
+        validate_upload_metadata("catch.jpg", "application/octet-stream")