From fbbe46e854a19f319e4ab789bc181c6e96411d6e Mon Sep 17 00:00:00 2001
From: "google-labs-jules[bot]"
 <161369871+google-labs-jules[bot]@users.noreply.github.com>
Date: Wed, 7 Oct 2026 03:55:52 +0000
Subject: [PATCH] test: add error handling test for SumEngine evaluate block

Co-authored-by: Horizontal42 <75383519+Horizontal42@users.noreply.github.com>
---
 src/engine/engine.test.ts | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/src/engine/engine.test.ts b/src/engine/engine.test.ts
index e8d8454..72d0f50 100644
--- a/src/engine/engine.test.ts
+++ b/src/engine/engine.test.ts
@@ -1,8 +1,9 @@
-import { describe, it, expect, beforeAll } from "vitest";
+import { describe, it, expect, beforeAll, vi } from "vitest";
 import { SumEngine } from "./index";
 import { qty, EvalError, XRefError } from "./types";
 import type { XRefResolution, EvalCtx } from "./evaluator";
 import { evaluate } from "./evaluator";
+import * as evaluator from "./evaluator";
 import { formatValue } from "./formatter";
 
 let eng: SumEngine;
@@ -451,4 +452,17 @@ describe("evaluation errors", () => {
     } as unknown as EvalCtx;
     expect(() => evaluate({ k: "xref", sheet: "Sheet", key: "key" }, ctx)).toThrowError(XRefError);
   });
+
+  it("catches and handles arbitrary errors in evaluateDocument", () => {
+    // Spy on evaluator.evaluate and force an arbitrary error
+    const spy = vi.spyOn(evaluator, "evaluate").mockImplementation(() => {
+      throw new Error("Forced execution anomaly");
+    });
+
+    const results = eng.evaluateDocument("1 + 1");
+    expect(results).toHaveLength(1);
+    expect(results[0].error).toBe("Forced execution anomaly");
+
+    spy.mockRestore();
+  });
 });