test: tidy concept-identity roundtrip docstring

surfsense_backend/tests/unit/agents/new_chat/test_path_resolver.py

@@ -79,6 +79,33 @@ class TestDocToVirtualPath:
         assert path == f"{DOCUMENTS_ROOT}/notes/A.xml"
 
 
+class TestConceptIdentityRoundTrip:
+    """A document's virtual path must parse back to the same (folder, title) - the
+    OKF path-identity guarantee at the grammar level, no DB required."""
+
+    def test_folder_nested_document_roundtrips(self):
+        index = PathIndex(folder_paths={5: f"{DOCUMENTS_ROOT}/Research/AI"})
+        path = doc_to_virtual_path(
+            doc_id=2, title="My Note", folder_id=5, index=index
+        )
+        assert path == f"{DOCUMENTS_ROOT}/Research/AI/My Note.xml"
+        folder_parts, title = parse_documents_path(path)
+        assert folder_parts == ["Research", "AI"]
+        assert title == "My Note"
+
+    def test_colliding_title_roundtrips_to_base_title(self):
+        # Second doc with the same title gets a " (<id>)" suffix; parsing the
+        # path must strip the disambiguator and recover the original title.
+        index = PathIndex(occupants={f"{DOCUMENTS_ROOT}/Hello.xml": 7})
+        path = doc_to_virtual_path(
+            doc_id=8, title="Hello", folder_id=None, index=index
+        )
+        assert path == f"{DOCUMENTS_ROOT}/Hello (8).xml"
+        folder_parts, title = parse_documents_path(path)
+        assert folder_parts == []
+        assert title == "Hello"
+
+
 class TestParseDocumentsPath:
     def test_extracts_folder_parts_and_title(self):
         parts, title = parse_documents_path(f"{DOCUMENTS_ROOT}/foo/bar/baz.xml")