fix(parsing): case-insensitive arXiv idno match; fix tmp_path types; add extract_structure test

Review-Gate finding: GROBID emits type="arXiv" (camel-case), not "arxiv".
XPath literal match silently returned empty strings for all real responses.
Fix: iterate idno elements and compare .lower() == "arxiv".
Test fixture updated to reflect real GROBID output (type="arXiv").

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

tests/parsing/test_grobid.py

@@ -2,13 +2,12 @@
 
 from __future__ import annotations
 
+from pathlib import Path
 from unittest.mock import MagicMock, patch
 
-import pytest
+from codex.parsing.grobid import extract_references, extract_structure
 
-from codex.parsing.grobid import extract_references
-
-# Minimal valid TEI XML with 2 biblStruct elements
+# Real GROBID TEI output uses type="arXiv" (camel-case), not "arxiv".
 _TEI_XML = """\
 <?xml version="1.0" encoding="UTF-8"?>
 <TEI xmlns="http://www.tei-c.org/ns/1.0">
@@ -32,7 +31,7 @@ _TEI_XML = """\
               </imprint>
             </monogr>
             <idno type="DOI">10.1234/nlp.2021</idno>
-            <idno type="arxiv">2101.00001</idno>
+            <idno type="arXiv">2101.00001</idno>
           </biblStruct>
           <biblStruct>
             <analytic>
@@ -73,28 +72,36 @@ class _FakeResponse:
         pass
 
 
+def _mock_post(xml: str = _TEI_XML) -> MagicMock:
+    fake = MagicMock()
+    fake.text = xml
+    fake.status_code = 200
+    fake.raise_for_status = MagicMock()
+    return fake
+
+
 class TestExtractReferences:
-    def test_returns_two_dicts(self, tmp_path: pytest.TempdirFactory) -> None:
-        pdf = tmp_path / "paper.pdf"  # type: ignore[operator]
+    def test_returns_two_dicts(self, tmp_path: Path) -> None:
+        pdf = tmp_path / "paper.pdf"
         pdf.write_bytes(b"%PDF fake")
 
         with patch("httpx.Client") as mock_client_cls:
             mock_client = MagicMock()
             mock_client_cls.return_value.__enter__.return_value = mock_client
-            mock_client.post.return_value = _FakeResponse()
+            mock_client.post.return_value = _mock_post()
 
             refs = extract_references(str(pdf), grobid_url="http://localhost:8070")
 
         assert len(refs) == 2
 
-    def test_all_keys_present(self, tmp_path: pytest.TempdirFactory) -> None:
-        pdf = tmp_path / "paper.pdf"  # type: ignore[operator]
+    def test_all_keys_present(self, tmp_path: Path) -> None:
+        pdf = tmp_path / "paper.pdf"
         pdf.write_bytes(b"%PDF fake")
 
         with patch("httpx.Client") as mock_client_cls:
             mock_client = MagicMock()
             mock_client_cls.return_value.__enter__.return_value = mock_client
-            mock_client.post.return_value = _FakeResponse()
+            mock_client.post.return_value = _mock_post()
 
             refs = extract_references(str(pdf), grobid_url="http://localhost:8070")
 
@@ -102,14 +109,14 @@ class TestExtractReferences:
         for ref in refs:
             assert required_keys == set(ref.keys()), f"Missing keys in {ref}"
 
-    def test_first_ref_values(self, tmp_path: pytest.TempdirFactory) -> None:
-        pdf = tmp_path / "paper.pdf"  # type: ignore[operator]
+    def test_first_ref_values(self, tmp_path: Path) -> None:
+        pdf = tmp_path / "paper.pdf"
         pdf.write_bytes(b"%PDF fake")
 
         with patch("httpx.Client") as mock_client_cls:
             mock_client = MagicMock()
             mock_client_cls.return_value.__enter__.return_value = mock_client
-            mock_client.post.return_value = _FakeResponse()
+            mock_client.post.return_value = _mock_post()
 
             refs = extract_references(str(pdf), grobid_url="http://localhost:8070")
 
@@ -120,16 +127,14 @@ class TestExtractReferences:
         assert first["doi"] == "10.1234/nlp.2021"
         assert first["arxiv_id"] == "2101.00001"
 
-    def test_second_ref_missing_arxiv_is_empty_string(
-        self, tmp_path: pytest.TempdirFactory
-    ) -> None:
-        pdf = tmp_path / "paper.pdf"  # type: ignore[operator]
+    def test_second_ref_missing_arxiv_is_empty_string(self, tmp_path: Path) -> None:
+        pdf = tmp_path / "paper.pdf"
         pdf.write_bytes(b"%PDF fake")
 
         with patch("httpx.Client") as mock_client_cls:
             mock_client = MagicMock()
             mock_client_cls.return_value.__enter__.return_value = mock_client
-            mock_client.post.return_value = _FakeResponse()
+            mock_client.post.return_value = _mock_post()
 
             refs = extract_references(str(pdf), grobid_url="http://localhost:8070")
 
@@ -137,3 +142,20 @@ class TestExtractReferences:
         assert second["arxiv_id"] == ""
         assert second["title"] == "Attention Is All You Need"
         assert second["year"] == "2017"
+
+
+class TestExtractStructure:
+    def test_returns_xml_string(self, tmp_path: Path) -> None:
+        pdf = tmp_path / "paper.pdf"
+        pdf.write_bytes(b"%PDF fake")
+
+        with patch("httpx.Client") as mock_client_cls:
+            mock_client = MagicMock()
+            mock_client_cls.return_value.__enter__.return_value = mock_client
+            mock_client.post.return_value = _mock_post("<TEI>raw xml</TEI>")
+
+            result = extract_structure(str(pdf), grobid_url="http://localhost:8070")
+
+        assert result == "<TEI>raw xml</TEI>"
+        mock_client.post.assert_called_once()
+        assert "processFulltextDocument" in mock_client.post.call_args[0][0]