From d2b9affbc519c54d438e3b6b74f930a0c3de6c8f Mon Sep 17 00:00:00 2001
From: vangel76 <vangel1976@googlemail.com>
Date: Sun, 11 Oct 2026 20:59:09 +0200
Subject: [PATCH] Functions: test that arithmetic reads a blank lookup result
 as 0 (#374)

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
---
 crates/calc/src/tests.rs | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/crates/calc/src/tests.rs b/crates/calc/src/tests.rs
index ac58b3d31..fe55dc3e1 100644
--- a/crates/calc/src/tests.rs
+++ b/crates/calc/src/tests.rs
@@ -986,6 +986,8 @@ fn lookup_of_an_empty_cell_stays_blank() {
         ("D7", "=ISBLANK(HLOOKUP(\"j\",A2:B3,2,0))", Value::Bool(true)),
         // A bare lookup still shows 0, like a reference to an empty cell.
         ("D8", "=VLOOKUP(\"k\",A1:B2,2,0)", Value::Number(0.0)),
+        // Arithmetic still reads the blank as 0.
+        ("D9", "=VLOOKUP(\"k\",A1:B2,2,0)+1", Value::Number(1.0)),
     ] {
         t.set(at, f);
         assert_eq!(t.get(at), want, "{f}");