From e38fc117ad0ef306b5572ea682dcea4b8a5f1861 Mon Sep 17 00:00:00 2001
From: Gatefixer <313497061+lancedb-gatefixer[bot]@users.noreply.github.com>
Date: Thu, 6 Aug 2026 04:26:01 +0000
Subject: [PATCH] test(python): cover arithmetic with distance projections

---
 python/python/tests/test_query.py | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/python/python/tests/test_query.py b/python/python/tests/test_query.py
index 6840be052..a3c94e7e8 100644
--- a/python/python/tests/test_query.py
+++ b/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]