test(python): cover arithmetic with distance projections

python/python/tests/test_query.py

@@ -666,6 +666,27 @@ def test_distance_range(table: lancedb.table.Table):
     assert res["_distance"].to_pylist() == [min_dist, max_dist]
 
 
+@pytest.mark.parametrize(
+    ("expression", "expected_type"),
+    [
+        ("1 - _distance", pa.float32()),
+        ("1.0 - _distance", pa.float64()),
+    ],
+)
+def test_select_arithmetic_with_distance(table, expression, expected_type):
+    result = (
+        table.search([10, 10])
+        .select({"similarity": expression})
+        .distance_type("cosine")
+        .to_arrow()
+    )
+
+    assert result.schema.field("similarity").type == expected_type
+    assert result["similarity"].to_pylist() == pytest.approx(
+        [1 - distance for distance in result["_distance"].to_pylist()]
+    )
+
+
 @pytest.mark.asyncio
 async def test_distance_range_async(table_async: AsyncTable):
     q = [0, 0]