fix: complete PPI and KaKs reference handoff

tests/unit/test_reference_bundle_download_progress.py

@@ -1,5 +1,6 @@
 from __future__ import annotations
 
+import http.client
 import zipfile
 
 
@@ -73,5 +74,51 @@ def test_reference_bundle_download_reports_progress_events(tmp_path, monkeypatch
     assert "validate_ids" in phases
     assert phases[-1] == "completed"
     assert manifest["requested_stages"] == ["ppi"]
-    assert manifest["requested_file_types"] == ["pep"]
-    assert "cds" not in manifest["files"]
+    assert manifest["requested_file_types"] == ["pep", "cds"]
+    assert "cds" in manifest["files"]
+
+
+def test_reference_bundle_download_retries_incomplete_read(tmp_path, monkeypatch):
+    from apps.web import pipeline_backend as backend
+
+    payload = b"complete archive"
+    calls = {"count": 0}
+
+    class FakeResponse:
+        def __init__(self, *, incomplete: bool):
+            self.incomplete = incomplete
+            self.headers = {"Content-Length": str(len(payload))}
+            self._sent = False
+
+        def __enter__(self):
+            return self
+
+        def __exit__(self, *_args):
+            return False
+
+        def read(self, _size):
+            if self.incomplete:
+                raise http.client.IncompleteRead(b"partial", len(payload))
+            if self._sent:
+                return b""
+            self._sent = True
+            return payload
+
+    def fake_urlopen(_url, timeout):
+        calls["count"] += 1
+        return FakeResponse(incomplete=calls["count"] == 1)
+
+    monkeypatch.setattr(backend.urllib.request, "urlopen", fake_urlopen)
+    monkeypatch.setattr(backend.time, "sleep", lambda _seconds: None)
+    output_path = tmp_path / "reference.zip"
+
+    downloaded = backend._download_url_to_file(
+        "https://example.invalid/reference.zip",
+        output_path,
+        attempts=2,
+    )
+
+    assert calls["count"] == 2
+    assert downloaded == len(payload)
+    assert output_path.read_bytes() == payload
+    assert not output_path.with_suffix(".zip.part").exists()