Thrash.

python/insta_science/_internal/fetcher.py

@@ -35,6 +35,7 @@
 from .hashing import Digest, ExpectedDigest, Fingerprint
 from .model import Url
 from .version import __version__
+from .. import Platform
 
 logger = logging.getLogger(__name__)
 
@@ -133,7 +134,16 @@ def _vet_request(url: Url, method: str = "GET") -> tuple[Request, Path] | Respon
         if request.method not in ("GET", "HEAD"):
             return Response(status_code=codes.METHOD_NOT_ALLOWED, request=request)
 
-        path = Path(urllib.parse.unquote_plus(url.info.path))
+        raw_path = urllib.parse.unquote_plus(url.info.path)
+        if Platform.current().is_windows:
+            # Handle `file:///C:/a/path` -> `C:/a/path`.
+            parts = raw_path.split("/")
+            if ":" == parts[1][-1]:
+                parts.pop(0)
+            path = Path("/".join(parts))
+        else:
+            path = Path(raw_path)
+
         if not path.exists():
             return Response(status_code=codes.NOT_FOUND, request=request)
         if not path.is_file():

python/tests/test_util.py

@@ -94,8 +94,6 @@ def test_download_file_mirror(pyproject_toml: Path, tmp_path: Path) -> None:
             """
         )
     )
-    if Platform.current().is_windows:
-        assert False, os.linesep.join((str(pyproject_toml), pyproject_toml.read_text()))
 
     subprocess.run(args=["insta-science-util", "download", mirror_dir], check=True)
     subprocess.run(args=["insta-science", "-V"], check=True)