diff --git a/src/shared/number-coercion.test.ts b/src/shared/number-coercion.test.ts
new file mode 100644
index 000000000000..4fcb00bf4b32
--- /dev/null
+++ b/src/shared/number-coercion.test.ts
@@ -0,0 +1,18 @@
+import { describe, expect, it } from "vitest";
+import { resolveNonNegativeNumber } from "./number-coercion.js";
+
+describe("resolveNonNegativeNumber", () => {
+  it.each([0, -0, 1.25, Number.MIN_VALUE, Number.MAX_VALUE])(
+    "preserves finite non-negative value %s",
+    (value) => {
+      expect(resolveNonNegativeNumber(value)).toBe(value);
+    },
+  );
+
+  it.each([-1, -0.1, Number.NaN, Infinity, -Infinity, null, undefined])(
+    "rejects invalid value %s",
+    (value) => {
+      expect(resolveNonNegativeNumber(value)).toBeUndefined();
+    },
+  );
+});