Chore: homepage tests (#6278)

src/utils/hooks/window-focus.test.jsx

@@ -0,0 +1,27 @@
+// @vitest-environment jsdom
+
+import { render, screen, waitFor } from "@testing-library/react";
+import { describe, expect, it, vi } from "vitest";
+
+import useWindowFocus from "./window-focus";
+
+function Fixture() {
+  const focused = useWindowFocus();
+  return <div data-testid="focused">{String(focused)}</div>;
+}
+
+describe("utils/hooks/window-focus", () => {
+  it("tracks focus/blur events", async () => {
+    vi.spyOn(document, "hasFocus").mockReturnValue(true);
+
+    render(<Fixture />);
+
+    expect(screen.getByTestId("focused")).toHaveTextContent("true");
+
+    window.dispatchEvent(new Event("blur"));
+    await waitFor(() => expect(screen.getByTestId("focused")).toHaveTextContent("false"));
+
+    window.dispatchEvent(new Event("focus"));
+    await waitFor(() => expect(screen.getByTestId("focused")).toHaveTextContent("true"));
+  });
+});