All of the mid-session and step-up auth work

clients/web/src/utils/browserTabVisibility.test.ts

@@ -0,0 +1,44 @@
+import { describe, it, expect, vi, beforeEach, afterEach } from "vitest";
+import {
+  isBrowserTabVisible,
+  onBrowserTabVisible,
+} from "./browserTabVisibility.js";
+
+describe("browserTabVisibility", () => {
+  beforeEach(() => {
+    vi.stubGlobal("document", {
+      visibilityState: "visible",
+      addEventListener: vi.fn(),
+      removeEventListener: vi.fn(),
+    });
+  });
+
+  afterEach(() => {
+    vi.unstubAllGlobals();
+  });
+
+  it("isBrowserTabVisible reflects document.visibilityState", () => {
+    expect(isBrowserTabVisible()).toBe(true);
+    (document as { visibilityState: string }).visibilityState = "hidden";
+    expect(isBrowserTabVisible()).toBe(false);
+  });
+
+  it("onBrowserTabVisible invokes callback when becoming visible", () => {
+    let handler: (() => void) | undefined;
+    vi.mocked(document.addEventListener).mockImplementation((_event, fn) => {
+      handler = fn as () => void;
+    });
+
+    const callback = vi.fn();
+    onBrowserTabVisible(callback);
+    expect(handler).toBeDefined();
+
+    (document as { visibilityState: string }).visibilityState = "hidden";
+    handler!();
+    expect(callback).not.toHaveBeenCalled();
+
+    (document as { visibilityState: string }).visibilityState = "visible";
+    handler!();
+    expect(callback).toHaveBeenCalledOnce();
+  });
+});