N-th fix od model DL

tests/test_node_startup.py

@@ -412,21 +412,15 @@ def test_download_shard_prefers_tracker_model_source_over_huggingface(
     monkeypatch,
 ):
     """A working tracker model source is used exclusively — HF is never contacted."""
-    source_dir = tmp_path / "source"
-    source_dir.mkdir()
-    (source_dir / "config.json").write_text("{}")
-    (source_dir / "model-00002-of-00004.safetensors").write_text("tracker")
-    archive = io.BytesIO()
-    with tarfile.open(fileobj=archive, mode="w") as tf:
-        tf.add(source_dir / "config.json", arcname="config.json")
-        tf.add(
-            source_dir / "model-00002-of-00004.safetensors",
-            arcname="model-00002-of-00004.safetensors",
-        )
+    contents = {
+        "config.json": b"{}",
+        "model-00002-of-00004.safetensors": b"tracker",
+    }
 
-    class FakeTrackerResponse:
+    class FakeFileResponse:
         def __init__(self, payload: bytes):
             self._payload = io.BytesIO(payload)
+            self._length = len(payload)
 
         def __enter__(self):
             return self
@@ -434,14 +428,23 @@ def test_download_shard_prefers_tracker_model_source_over_huggingface(
         def __exit__(self, exc_type, exc, tb):
             return False
 
+        def getheader(self, name: str):
+            if name == "Content-Length":
+                return str(self._length)
+            if name == "Content-Type":
+                return "application/octet-stream"
+            return None
+
         def read(self, size: int = -1) -> bytes:
             return self._payload.read(size)
 
-    monkeypatch.setattr(
-        urllib.request,
-        "urlopen",
-        lambda *args, **kwargs: FakeTrackerResponse(archive.getvalue()),
-    )
+    def fake_urlopen(url, *args, **kwargs):
+        query = urllib.parse.parse_qs(urllib.parse.urlparse(url).query)
+        rel = query.get("file", [None])[0]
+        assert rel in contents, f"unexpected per-file request: {url}"
+        return FakeFileResponse(contents[rel])
+
+    monkeypatch.setattr(urllib.request, "urlopen", fake_urlopen)
     hf_calls = []
 
     def fake_snapshot_download(**kwargs):