add tests for useForceUpdate

packages/utils/__tests__/use-force-update.test.tsx

@@ -0,0 +1,34 @@
+/// <reference types="vitest-dom/extend-expect" />
+
+import * as React from "react";
+import { render, cleanup, userEvent } from "@reach-internal/test/utils";
+import { afterEach, describe, expect, it } from "vitest";
+import { useForceUpdate } from "@reach/utils";
+
+afterEach(cleanup);
+
+describe("useForceUpdate", () => {
+	it("should force rerender when called", async () => {
+		let nonObservableVariable = "foo";
+
+		const Test = () => {
+			const forceUpdate = useForceUpdate();
+			return (
+				<>
+					<div data-testid="div">{nonObservableVariable}</div>
+					<button data-testid="button" onClick={forceUpdate} />
+				</>
+			);
+		};
+
+		const { getByTestId } = render(<Test />);
+		const div = getByTestId("div");
+		const button = getByTestId("button");
+
+		expect(div).toHaveTextContent("foo");
+		nonObservableVariable = "bar";
+		expect(div).toHaveTextContent("foo");
+		await userEvent.click(button);
+		expect(div).toHaveTextContent("bar");
+	});
+});