diff --git a/src/ui/search.test.ts b/src/ui/search.test.ts
new file mode 100644
index 0000000..f1cae41
--- /dev/null
+++ b/src/ui/search.test.ts
@@ -0,0 +1,99 @@
+import { describe, it, expect } from "vitest";
+import { SumEngine } from "../engine";
+import { parseResultQuery } from "./search";
+import Decimal from "decimal.js";
+
+describe("parseResultQuery", () => {
+  const engine = new SumEngine();
+
+  it("parses '>=' operator correctly", () => {
+    const res = parseResultQuery(engine, ">= 100");
+    expect(res).not.toBeNull();
+    expect(res?.op).toBe(">=");
+    expect(res?.threshold.kind).toBe("quantity");
+    if (res?.threshold.kind === "quantity") {
+      expect(res.threshold.value.eq(new Decimal(100))).toBe(true);
+    }
+  });
+
+  it("parses '<=' operator correctly", () => {
+    const res = parseResultQuery(engine, "<= 50");
+    expect(res).not.toBeNull();
+    expect(res?.op).toBe("<=");
+    expect(res?.threshold.kind).toBe("quantity");
+    if (res?.threshold.kind === "quantity") {
+      expect(res.threshold.value.eq(new Decimal(50))).toBe(true);
+    }
+  });
+
+  it("parses '>' operator correctly", () => {
+    const res = parseResultQuery(engine, "> 0");
+    expect(res).not.toBeNull();
+    expect(res?.op).toBe(">");
+    expect(res?.threshold.kind).toBe("quantity");
+    if (res?.threshold.kind === "quantity") {
+      expect(res.threshold.value.eq(new Decimal(0))).toBe(true);
+    }
+  });
+
+  it("parses '<' operator correctly", () => {
+    const res = parseResultQuery(engine, "< -10");
+    expect(res).not.toBeNull();
+    expect(res?.op).toBe("<");
+    expect(res?.threshold.kind).toBe("quantity");
+    if (res?.threshold.kind === "quantity") {
+      expect(res.threshold.value.eq(new Decimal(-10))).toBe(true);
+    }
+  });
+
+  it("parses '=' operator correctly", () => {
+    const res = parseResultQuery(engine, "= 42.5");
+    expect(res).not.toBeNull();
+    expect(res?.op).toBe("=");
+    expect(res?.threshold.kind).toBe("quantity");
+    if (res?.threshold.kind === "quantity") {
+      expect(res.threshold.value.eq(new Decimal(42.5))).toBe(true);
+    }
+  });
+
+  it("parses '~' operator correctly", () => {
+    const res = parseResultQuery(engine, "~ 3.14");
+    expect(res).not.toBeNull();
+    expect(res?.op).toBe("~");
+    expect(res?.threshold.kind).toBe("quantity");
+    if (res?.threshold.kind === "quantity") {
+      expect(res.threshold.value.eq(new Decimal(3.14))).toBe(true);
+    }
+  });
+
+  it("handles whitespace correctly", () => {
+    const res = parseResultQuery(engine, "   >=    200   ");
+    expect(res).not.toBeNull();
+    expect(res?.op).toBe(">=");
+    expect(res?.threshold.kind).toBe("quantity");
+    if (res?.threshold.kind === "quantity") {
+      expect(res.threshold.value.eq(new Decimal(200))).toBe(true);
+    }
+  });
+
+  it("returns null for invalid operator", () => {
+    const res = parseResultQuery(engine, "!= 100");
+    expect(res).toBeNull();
+  });
+
+  it("returns null for invalid value string", () => {
+    // "abc" cannot be evaluated to a quantity
+    const res = parseResultQuery(engine, ">= abc");
+    expect(res).toBeNull();
+  });
+
+  it("returns null for empty string", () => {
+    const res = parseResultQuery(engine, "");
+    expect(res).toBeNull();
+  });
+
+  it("returns null when no expression matches after operator", () => {
+    const res = parseResultQuery(engine, ">=");
+    expect(res).toBeNull();
+  });
+});
diff --git a/src/ui/search.ts b/src/ui/search.ts
index 7b332a0..97f3671 100644
--- a/src/ui/search.ts
+++ b/src/ui/search.ts
@@ -32,7 +32,7 @@ export interface SearchController {
 
 const $ = <T extends HTMLElement>(sel: string): T => document.querySelector(sel) as T;
 
-function parseResultQuery(engine: SumEngine, q: string): { op: string; threshold: Value } | null {
+export function parseResultQuery(engine: SumEngine, q: string): { op: string; threshold: Value } | null {
   const m = /^(>=|<=|>|<|=|~)\s*(.+)$/.exec(q.trim());
   if (!m) return null;
   const v = engine.evaluateExpression(m[2].trim());