Added vector relationship query tests

tests/unit/test_neo4j_queries.py

@@ -15,8 +15,9 @@
 from typing import Any
 from unittest.mock import patch
 
+import pytest
 from neo4j_graphrag.neo4j_queries import get_query_tail, get_search_query
-from neo4j_graphrag.types import SearchType
+from neo4j_graphrag.types import IndexType, SearchType
 
 
 def test_vector_search_basic() -> None:
@@ -31,6 +32,34 @@ def test_vector_search_basic() -> None:
     assert params == {}
 
 
+def test_rel_vector_search_basic() -> None:
+    expected = (
+        "CALL db.index.vector.queryRelationships($vector_index_name, $top_k * $effective_search_ratio, $query_vector) "
+        "YIELD relationship, score "
+        "WITH relationship, score LIMIT $top_k "
+        "RETURN relationship { .*, `None`: null } AS relationship, elementId(relationship) AS elementId, score"
+    )
+    result, params = get_search_query(SearchType.VECTOR, IndexType.RELATIONSHIP)
+    assert result.strip() == expected.strip()
+    assert params == {}
+
+
+def test_rel_vector_search_filters_err() -> None:
+    with pytest.raises(Exception) as exc_info:
+        get_search_query(
+            SearchType.VECTOR, IndexType.RELATIONSHIP, filters={"filter": None}
+        )
+    assert str(exc_info.value) == "Filters are not supported for relationship indexes"
+
+
+def test_rel_vector_search_hybrid_err() -> None:
+    with pytest.raises(Exception) as exc_info:
+        get_search_query(SearchType.HYBRID, IndexType.RELATIONSHIP)
+    assert (
+        str(exc_info.value) == "Hybrid search is not supported for relationship indexes"
+    )
+
+
 def test_hybrid_search_basic() -> None:
     expected = (
         "CALL { "