Add admin UX improvements, constants refactor, and comprehensive tests

- Introduced constants for admin hooks: `STATS_FETCH_LIMIT`, `DEFAULT_PAGE_LIMIT`, and `STATS_REFETCH_INTERVAL` to enhance readability and maintainability.
- Updated query guards to ensure data fetching is restricted to superusers.
- Enhanced accessibility across admin components by adding `aria-hidden` attributes and improving focus-visible styles.
- Simplified `useAdminStats`, `useAdminUsers`, and `useAdminOrganizations` with shared constants.
- Added 403 Forbidden page with proper structure, styling, and tests.
- Implemented new tests for admin hooks, DashboardStats, AdminLayout, and ForbiddenPage for better coverage.

frontend/src/app/admin/layout.tsx

@@ -24,13 +24,19 @@ export default function AdminLayout({
 }) {
   return (
     <AuthGuard requireAdmin>
+      <a
+        href="#main-content"
+        className="sr-only focus:not-sr-only focus:absolute focus:left-4 focus:top-4 focus:z-50 focus:rounded-md focus:bg-primary focus:px-4 focus:py-2 focus:text-primary-foreground focus:outline-none focus:ring-2 focus:ring-ring focus:ring-offset-2"
+      >
+        Skip to main content
+      </a>
       <div className="flex min-h-screen flex-col">
         <Header />
         <div className="flex flex-1">
           <AdminSidebar />
           <div className="flex flex-1 flex-col">
             <Breadcrumbs />
-            <main className="flex-1 overflow-y-auto">
+            <main id="main-content" className="flex-1 overflow-y-auto">
               {children}
             </main>
           </div>

frontend/src/app/admin/organizations/page.tsx

@@ -22,8 +22,8 @@ export default function AdminOrganizationsPage() {
         {/* Back Button + Header */}
         <div className="flex items-center gap-4">
           <Link href="/admin">
-            <Button variant="outline" size="icon">
-              <ArrowLeft className="h-4 w-4" />
+            <Button variant="outline" size="icon" aria-label="Back to Admin Dashboard">
+              <ArrowLeft className="h-4 w-4" aria-hidden="true" />
             </Button>
           </Link>
           <div>

frontend/src/app/admin/page.tsx

@@ -39,7 +39,7 @@ export default function AdminPage() {
             <Link href="/admin/users" className="block">
               <div className="rounded-lg border bg-card p-6 transition-colors hover:bg-accent cursor-pointer">
                 <div className="flex items-center gap-3 mb-2">
-                  <Users className="h-5 w-5 text-primary" />
+                  <Users className="h-5 w-5 text-primary" aria-hidden="true" />
                   <h3 className="font-semibold">User Management</h3>
                 </div>
                 <p className="text-sm text-muted-foreground">
@@ -51,7 +51,7 @@ export default function AdminPage() {
             <Link href="/admin/organizations" className="block">
               <div className="rounded-lg border bg-card p-6 transition-colors hover:bg-accent cursor-pointer">
                 <div className="flex items-center gap-3 mb-2">
-                  <Building2 className="h-5 w-5 text-primary" />
+                  <Building2 className="h-5 w-5 text-primary" aria-hidden="true" />
                   <h3 className="font-semibold">Organizations</h3>
                 </div>
                 <p className="text-sm text-muted-foreground">
@@ -63,7 +63,7 @@ export default function AdminPage() {
             <Link href="/admin/settings" className="block">
               <div className="rounded-lg border bg-card p-6 transition-colors hover:bg-accent cursor-pointer">
                 <div className="flex items-center gap-3 mb-2">
-                  <Settings className="h-5 w-5 text-primary" />
+                  <Settings className="h-5 w-5 text-primary" aria-hidden="true" />
                   <h3 className="font-semibold">System Settings</h3>
                 </div>
                 <p className="text-sm text-muted-foreground">

frontend/src/app/admin/settings/page.tsx

@@ -22,8 +22,8 @@ export default function AdminSettingsPage() {
         {/* Back Button + Header */}
         <div className="flex items-center gap-4">
           <Link href="/admin">
-            <Button variant="outline" size="icon">
-              <ArrowLeft className="h-4 w-4" />
+            <Button variant="outline" size="icon" aria-label="Back to Admin Dashboard">
+              <ArrowLeft className="h-4 w-4" aria-hidden="true" />
             </Button>
           </Link>
           <div>

frontend/src/app/forbidden/page.tsx

@@ -0,0 +1,53 @@
+/**
+ * 403 Forbidden Page
+ * Displayed when users try to access resources they don't have permission for
+ */
+
+/* istanbul ignore next - Next.js type import for metadata */
+import type { Metadata } from 'next';
+import Link from 'next/link';
+import { ShieldAlert } from 'lucide-react';
+import { Button } from '@/components/ui/button';
+
+/* istanbul ignore next - Next.js metadata, not executable code */
+export const metadata: Metadata = {
+  title: '403 - Forbidden',
+  description: 'You do not have permission to access this resource',
+};
+
+export default function ForbiddenPage() {
+  return (
+    <div className="container mx-auto px-6 py-16">
+      <div className="flex min-h-[60vh] flex-col items-center justify-center text-center">
+        <div className="mb-8 rounded-full bg-destructive/10 p-6">
+          <ShieldAlert
+            className="h-16 w-16 text-destructive"
+            aria-hidden="true"
+          />
+        </div>
+
+        <h1 className="mb-4 text-4xl font-bold tracking-tight">
+          403 - Access Forbidden
+        </h1>
+
+        <p className="mb-2 text-lg text-muted-foreground max-w-md">
+          You don&apos;t have permission to access this resource.
+        </p>
+
+        <p className="mb-8 text-sm text-muted-foreground max-w-md">
+          This page requires administrator privileges. If you believe you should
+          have access, please contact your system administrator.
+        </p>
+
+        <div className="flex gap-4">
+          <Button asChild variant="default">
+            <Link href="/dashboard">Go to Dashboard</Link>
+          </Button>
+          <Button asChild variant="outline">
+            <Link href="/">Go to Home</Link>
+          </Button>
+        </div>
+      </div>
+    </div>
+  );
+}

frontend/src/components/admin/AdminSidebar.tsx

@@ -69,14 +69,14 @@ export function AdminSidebar() {
           )}
           <button
             onClick={() => setCollapsed(!collapsed)}
-            className="rounded-md p-2 hover:bg-accent"
+            className="rounded-md p-2 hover:bg-accent focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-ring focus-visible:ring-offset-2"
             aria-label={collapsed ? 'Expand sidebar' : 'Collapse sidebar'}
             data-testid="sidebar-toggle"
           >
             {collapsed ? (
-              <ChevronRight className="h-4 w-4" />
+              <ChevronRight className="h-4 w-4" aria-hidden="true" />
             ) : (
-              <ChevronLeft className="h-4 w-4" />
+              <ChevronLeft className="h-4 w-4" aria-hidden="true" />
             )}
           </button>
         </div>
@@ -96,6 +96,7 @@ export function AdminSidebar() {
                 className={cn(
                   'flex items-center gap-3 rounded-md px-3 py-2 text-sm font-medium transition-colors',
                   'hover:bg-accent hover:text-accent-foreground',
+                  'focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-ring focus-visible:ring-offset-2',
                   isActive
                     ? 'bg-accent text-accent-foreground'
                     : 'text-muted-foreground',
@@ -104,7 +105,7 @@ export function AdminSidebar() {
                 title={collapsed ? item.name : undefined}
                 data-testid={`nav-${item.name.toLowerCase()}`}
               >
-                <Icon className="h-5 w-5 flex-shrink-0" />
+                <Icon className="h-5 w-5 flex-shrink-0" aria-hidden="true" />
                 {!collapsed && <span>{item.name}</span>}
               </Link>
             );

frontend/src/components/admin/DashboardStats.tsx

@@ -17,7 +17,7 @@ export function DashboardStats() {
   if (isError) {
     return (
       <Alert variant="destructive">
-        <AlertCircle className="h-4 w-4" />
+        <AlertCircle className="h-4 w-4" aria-hidden="true" />
         <AlertDescription>
           Failed to load dashboard statistics: {error?.message || 'Unknown error'}
         </AlertDescription>

frontend/src/components/admin/StatCard.tsx

@@ -90,6 +90,7 @@ export function StatCard({
               'h-6 w-6',
               loading ? 'text-muted-foreground' : 'text-primary'
             )}
+            aria-hidden="true"
           />
         </div>
       </div>

frontend/src/lib/api/hooks/useAdmin.tsx

@@ -13,6 +13,14 @@
 
 import { useQuery } from '@tanstack/react-query';
 import { adminListUsers, adminListOrganizations } from '@/lib/api/client';
+import { useAuth } from '@/lib/auth/AuthContext';
+
+/**
+ * Constants for admin hooks
+ */
+const STATS_FETCH_LIMIT = 10000; // High limit to fetch all records for stats calculation
+const STATS_REFETCH_INTERVAL = 30000; // 30 seconds - refetch interval for near real-time stats
+const DEFAULT_PAGE_LIMIT = 50; // Default number of records per page for paginated lists
 
 /**
  * Admin Stats interface
@@ -31,6 +39,8 @@ export interface AdminStats {
  * @returns Admin statistics including user and organization counts
  */
 export function useAdminStats() {
+  const { user } = useAuth();
+
   return useQuery({
     queryKey: ['admin', 'stats'],
     queryFn: async (): Promise<AdminStats> => {
@@ -39,7 +49,7 @@ export function useAdminStats() {
       const usersResponse = await adminListUsers({
         query: {
           page: 1,
-          limit: 10000, // High limit to get all users for stats
+          limit: STATS_FETCH_LIMIT,
         },
         throwOnError: false,
       });
@@ -58,7 +68,7 @@ export function useAdminStats() {
       const orgsResponse = await adminListOrganizations({
         query: {
           page: 1,
-          limit: 10000, // High limit to get all orgs for stats
+          limit: STATS_FETCH_LIMIT,
         },
         throwOnError: false,
       });
@@ -93,9 +103,11 @@ export function useAdminStats() {
       };
     },
     // Refetch every 30 seconds for near real-time stats
-    refetchInterval: 30000,
+    refetchInterval: STATS_REFETCH_INTERVAL,
     // Keep previous data while refetching to avoid UI flicker
     placeholderData: (previousData) => previousData,
+    // Only fetch if user is a superuser (frontend guard)
+    enabled: user?.is_superuser === true,
   });
 }
 
@@ -106,7 +118,9 @@ export function useAdminStats() {
  * @param limit - Number of records per page
  * @returns Paginated list of users
  */
-export function useAdminUsers(page = 1, limit = 50) {
+export function useAdminUsers(page = 1, limit = DEFAULT_PAGE_LIMIT) {
+  const { user } = useAuth();
+
   return useQuery({
     queryKey: ['admin', 'users', page, limit],
     queryFn: async () => {
@@ -122,6 +136,8 @@ export function useAdminUsers(page = 1, limit = 50) {
       // Type assertion: if no error, response has data
       return (response as { data: unknown }).data;
     },
+    // Only fetch if user is a superuser (frontend guard)
+    enabled: user?.is_superuser === true,
   });
 }
 
@@ -132,7 +148,9 @@ export function useAdminUsers(page = 1, limit = 50) {
  * @param limit - Number of records per page
  * @returns Paginated list of organizations
  */
-export function useAdminOrganizations(page = 1, limit = 50) {
+export function useAdminOrganizations(page = 1, limit = DEFAULT_PAGE_LIMIT) {
+  const { user } = useAuth();
+
   return useQuery({
     queryKey: ['admin', 'organizations', page, limit],
     queryFn: async () => {
@@ -148,5 +166,7 @@ export function useAdminOrganizations(page = 1, limit = 50) {
       // Type assertion: if no error, response has data
       return (response as { data: unknown }).data;
     },
+    // Only fetch if user is a superuser (frontend guard)
+    enabled: user?.is_superuser === true,
   });
 }

frontend/tests/app/admin/layout.test.tsx

@@ -0,0 +1,169 @@
+/**
+ * Tests for Admin Layout
+ * Verifies layout rendering, auth guard, and accessibility features
+ */
+
+import { render, screen } from '@testing-library/react';
+import { QueryClient, QueryClientProvider } from '@tanstack/react-query';
+import AdminLayout from '@/app/admin/layout';
+import { useAuth } from '@/lib/auth/AuthContext';
+
+// Mock dependencies
+jest.mock('@/lib/auth/AuthContext');
+jest.mock('@/components/layout/Header', () => ({
+  Header: () => <header data-testid="header">Header</header>,
+}));
+jest.mock('@/components/layout/Footer', () => ({
+  Footer: () => <footer data-testid="footer">Footer</footer>,
+}));
+jest.mock('@/components/admin/AdminSidebar', () => ({
+  AdminSidebar: () => <aside data-testid="sidebar">Sidebar</aside>,
+}));
+jest.mock('@/components/admin/Breadcrumbs', () => ({
+  Breadcrumbs: () => <div data-testid="breadcrumbs">Breadcrumbs</div>,
+}));
+
+// Mock next/navigation
+jest.mock('next/navigation', () => ({
+  useRouter: () => ({
+    push: jest.fn(),
+    replace: jest.fn(),
+    prefetch: jest.fn(),
+  }),
+  usePathname: () => '/admin',
+}));
+
+const mockUseAuth = useAuth as jest.MockedFunction<typeof useAuth>;
+
+describe('AdminLayout', () => {
+  let queryClient: QueryClient;
+
+  beforeEach(() => {
+    queryClient = new QueryClient({
+      defaultOptions: {
+        queries: {
+          retry: false,
+        },
+      },
+    });
+    jest.clearAllMocks();
+  });
+
+  const wrapper = ({ children }: { children: React.ReactNode }) => (
+    <QueryClientProvider client={queryClient}>
+      {children}
+    </QueryClientProvider>
+  );
+
+  it('renders layout with all components for superuser', () => {
+    mockUseAuth.mockReturnValue({
+      user: { is_superuser: true } as any,
+      isAuthenticated: true,
+      isLoading: false,
+      login: jest.fn(),
+      logout: jest.fn(),
+    });
+
+    render(
+      <AdminLayout>
+        <div>Test Content</div>
+      </AdminLayout>,
+      { wrapper }
+    );
+
+    expect(screen.getByTestId('header')).toBeInTheDocument();
+    expect(screen.getByTestId('footer')).toBeInTheDocument();
+    expect(screen.getByTestId('sidebar')).toBeInTheDocument();
+    expect(screen.getByTestId('breadcrumbs')).toBeInTheDocument();
+    expect(screen.getByText('Test Content')).toBeInTheDocument();
+  });
+
+  it('renders skip link with correct attributes', () => {
+    mockUseAuth.mockReturnValue({
+      user: { is_superuser: true } as any,
+      isAuthenticated: true,
+      isLoading: false,
+      login: jest.fn(),
+      logout: jest.fn(),
+    });
+
+    render(
+      <AdminLayout>
+        <div>Test Content</div>
+      </AdminLayout>,
+      { wrapper }
+    );
+
+    const skipLink = screen.getByText('Skip to main content');
+    expect(skipLink).toBeInTheDocument();
+    expect(skipLink).toHaveAttribute('href', '#main-content');
+    expect(skipLink).toHaveClass('sr-only');
+  });
+
+  it('renders main element with id', () => {
+    mockUseAuth.mockReturnValue({
+      user: { is_superuser: true } as any,
+      isAuthenticated: true,
+      isLoading: false,
+      login: jest.fn(),
+      logout: jest.fn(),
+    });
+
+    const { container } = render(
+      <AdminLayout>
+        <div>Test Content</div>
+      </AdminLayout>,
+      { wrapper }
+    );
+
+    const mainElement = container.querySelector('#main-content');
+    expect(mainElement).toBeInTheDocument();
+    expect(mainElement?.tagName).toBe('MAIN');
+  });
+
+  it('renders children inside main content area', () => {
+    mockUseAuth.mockReturnValue({
+      user: { is_superuser: true } as any,
+      isAuthenticated: true,
+      isLoading: false,
+      login: jest.fn(),
+      logout: jest.fn(),
+    });
+
+    render(
+      <AdminLayout>
+        <div data-testid="child-content">Child Content</div>
+      </AdminLayout>,
+      { wrapper }
+    );
+
+    const mainElement = screen.getByTestId('child-content').closest('main');
+    expect(mainElement).toHaveAttribute('id', 'main-content');
+  });
+
+  it('applies correct layout structure classes', () => {
+    mockUseAuth.mockReturnValue({
+      user: { is_superuser: true } as any,
+      isAuthenticated: true,
+      isLoading: false,
+      login: jest.fn(),
+      logout: jest.fn(),
+    });
+
+    const { container } = render(
+      <AdminLayout>
+        <div>Test Content</div>
+      </AdminLayout>,
+      { wrapper }
+    );
+
+    // Check root container has min-height class
+    const rootDiv = container.querySelector('.min-h-screen');
+    expect(rootDiv).toBeInTheDocument();
+    expect(rootDiv).toHaveClass('flex', 'flex-col');
+
+    // Check main content area has flex and overflow classes
+    const mainElement = container.querySelector('#main-content');
+    expect(mainElement).toHaveClass('flex-1', 'overflow-y-auto');
+  });
+});

frontend/tests/app/admin/page.test.tsx

@@ -4,35 +4,44 @@
  */
 
 import { render, screen } from '@testing-library/react';
-import { QueryClient, QueryClientProvider } from '@tanstack/react-query';
 import AdminPage from '@/app/admin/page';
+import { useAdminStats } from '@/lib/api/hooks/useAdmin';
 
-// Helper function to render with QueryClientProvider
-function renderWithQueryClient(component: React.ReactElement) {
-  const queryClient = new QueryClient({
-    defaultOptions: {
-      queries: {
-        retry: false,
-      },
+// Mock the useAdminStats hook
+jest.mock('@/lib/api/hooks/useAdmin');
+
+const mockUseAdminStats = useAdminStats as jest.MockedFunction<typeof useAdminStats>;
+
+// Helper function to render with default mocked stats
+function renderWithMockedStats() {
+  mockUseAdminStats.mockReturnValue({
+    data: {
+      totalUsers: 100,
+      activeUsers: 80,
+      totalOrganizations: 20,
+      totalSessions: 30,
     },
-  });
+    isLoading: false,
+    isError: false,
+    error: null,
+  } as any);
 
-  return render(
-    <QueryClientProvider client={queryClient}>
-      {component}
-    </QueryClientProvider>
-  );
+  return render(<AdminPage />);
 }
 
 describe('AdminPage', () => {
+  beforeEach(() => {
+    jest.clearAllMocks();
+  });
+
   it('renders admin dashboard title', () => {
-    renderWithQueryClient(<AdminPage />);
+    renderWithMockedStats();
 
     expect(screen.getByText('Admin Dashboard')).toBeInTheDocument();
   });
 
   it('renders description text', () => {
-    renderWithQueryClient(<AdminPage />);
+    renderWithMockedStats();
 
     expect(
       screen.getByText('Manage users, organizations, and system settings')
@@ -40,13 +49,13 @@ describe('AdminPage', () => {
   });
 
   it('renders quick actions section', () => {
-    renderWithQueryClient(<AdminPage />);
+    renderWithMockedStats();
 
     expect(screen.getByText('Quick Actions')).toBeInTheDocument();
   });
 
   it('renders user management card', () => {
-    renderWithQueryClient(<AdminPage />);
+    renderWithMockedStats();
 
     expect(screen.getByText('User Management')).toBeInTheDocument();
     expect(
@@ -55,7 +64,7 @@ describe('AdminPage', () => {
   });
 
   it('renders organizations card', () => {
-    renderWithQueryClient(<AdminPage />);
+    renderWithMockedStats();
 
     // Check for the quick actions card (not the stat card)
     expect(
@@ -64,7 +73,7 @@ describe('AdminPage', () => {
   });
 
   it('renders system settings card', () => {
-    renderWithQueryClient(<AdminPage />);
+    renderWithMockedStats();
 
     expect(screen.getByText('System Settings')).toBeInTheDocument();
     expect(
@@ -73,7 +82,7 @@ describe('AdminPage', () => {
   });
 
   it('renders quick actions in grid layout', () => {
-    renderWithQueryClient(<AdminPage />);
+    renderWithMockedStats();
 
     // Check for Quick Actions heading which is above the grid
     expect(screen.getByText('Quick Actions')).toBeInTheDocument();
@@ -84,7 +93,7 @@ describe('AdminPage', () => {
   });
 
   it('renders with proper container structure', () => {
-    const { container } = renderWithQueryClient(<AdminPage />);
+    const { container } = renderWithMockedStats();
 
     const containerDiv = container.querySelector('.container');
     expect(containerDiv).toBeInTheDocument();

frontend/tests/app/forbidden/page.test.tsx

@@ -0,0 +1,66 @@
+/**
+ * Tests for 403 Forbidden Page
+ * Verifies rendering of access forbidden message and navigation
+ */
+
+import { render, screen } from '@testing-library/react';
+import ForbiddenPage from '@/app/forbidden/page';
+
+describe('ForbiddenPage', () => {
+  it('renders page heading', () => {
+    render(<ForbiddenPage />);
+
+    expect(
+      screen.getByRole('heading', { name: /403 - Access Forbidden/i })
+    ).toBeInTheDocument();
+  });
+
+  it('renders permission denied message', () => {
+    render(<ForbiddenPage />);
+
+    expect(
+      screen.getByText(/You don't have permission to access this resource/)
+    ).toBeInTheDocument();
+  });
+
+  it('renders admin privileges message', () => {
+    render(<ForbiddenPage />);
+
+    expect(
+      screen.getByText(/This page requires administrator privileges/)
+    ).toBeInTheDocument();
+  });
+
+  it('renders link to dashboard', () => {
+    render(<ForbiddenPage />);
+
+    const dashboardLink = screen.getByRole('link', {
+      name: /Go to Dashboard/i,
+    });
+    expect(dashboardLink).toBeInTheDocument();
+    expect(dashboardLink).toHaveAttribute('href', '/dashboard');
+  });
+
+  it('renders link to home', () => {
+    render(<ForbiddenPage />);
+
+    const homeLink = screen.getByRole('link', { name: /Go to Home/i });
+    expect(homeLink).toBeInTheDocument();
+    expect(homeLink).toHaveAttribute('href', '/');
+  });
+
+  it('renders shield alert icon with aria-hidden', () => {
+    const { container } = render(<ForbiddenPage />);
+
+    const icon = container.querySelector('[aria-hidden="true"]');
+    expect(icon).toBeInTheDocument();
+  });
+
+  it('renders with proper container structure', () => {
+    const { container } = render(<ForbiddenPage />);
+
+    const containerDiv = container.querySelector('.container');
+    expect(containerDiv).toBeInTheDocument();
+    expect(containerDiv).toHaveClass('mx-auto', 'px-6', 'py-16');
+  });
+});

frontend/tests/components/admin/DashboardStats.test.tsx

@@ -0,0 +1,157 @@
+/**
+ * Tests for DashboardStats Component
+ * Verifies dashboard statistics display and error handling
+ */
+
+import { render, screen } from '@testing-library/react';
+import { DashboardStats } from '@/components/admin/DashboardStats';
+import { useAdminStats } from '@/lib/api/hooks/useAdmin';
+
+// Mock the useAdminStats hook
+jest.mock('@/lib/api/hooks/useAdmin');
+
+const mockUseAdminStats = useAdminStats as jest.MockedFunction<typeof useAdminStats>;
+
+describe('DashboardStats', () => {
+  beforeEach(() => {
+    jest.clearAllMocks();
+  });
+
+  it('renders all stat cards with data', () => {
+    mockUseAdminStats.mockReturnValue({
+      data: {
+        totalUsers: 150,
+        activeUsers: 120,
+        totalOrganizations: 25,
+        totalSessions: 45,
+      },
+      isLoading: false,
+      isError: false,
+      error: null,
+    } as any);
+
+    render(<DashboardStats />);
+
+    // Check stat cards are rendered
+    expect(screen.getByText('Total Users')).toBeInTheDocument();
+    expect(screen.getByText('150')).toBeInTheDocument();
+    expect(screen.getByText('All registered users')).toBeInTheDocument();
+
+    expect(screen.getByText('Active Users')).toBeInTheDocument();
+    expect(screen.getByText('120')).toBeInTheDocument();
+    expect(screen.getByText('Users with active status')).toBeInTheDocument();
+
+    expect(screen.getByText('Organizations')).toBeInTheDocument();
+    expect(screen.getByText('25')).toBeInTheDocument();
+    expect(screen.getByText('Total organizations')).toBeInTheDocument();
+
+    expect(screen.getByText('Active Sessions')).toBeInTheDocument();
+    expect(screen.getByText('45')).toBeInTheDocument();
+    expect(screen.getByText('Current active sessions')).toBeInTheDocument();
+  });
+
+  it('renders loading state', () => {
+    mockUseAdminStats.mockReturnValue({
+      data: undefined,
+      isLoading: true,
+      isError: false,
+      error: null,
+    } as any);
+
+    render(<DashboardStats />);
+
+    // StatCard component should render loading state
+    expect(screen.getByText('Total Users')).toBeInTheDocument();
+    expect(screen.getByText('Active Users')).toBeInTheDocument();
+    expect(screen.getByText('Organizations')).toBeInTheDocument();
+    expect(screen.getByText('Active Sessions')).toBeInTheDocument();
+  });
+
+  it('renders error state', () => {
+    mockUseAdminStats.mockReturnValue({
+      data: undefined,
+      isLoading: false,
+      isError: true,
+      error: new Error('Network error occurred'),
+    } as any);
+
+    render(<DashboardStats />);
+
+    expect(screen.getByText(/Failed to load dashboard statistics/)).toBeInTheDocument();
+    expect(screen.getByText(/Network error occurred/)).toBeInTheDocument();
+  });
+
+  it('renders error state with default message when error message is missing', () => {
+    mockUseAdminStats.mockReturnValue({
+      data: undefined,
+      isLoading: false,
+      isError: true,
+      error: {} as any,
+    } as any);
+
+    render(<DashboardStats />);
+
+    expect(screen.getByText(/Failed to load dashboard statistics/)).toBeInTheDocument();
+    expect(screen.getByText(/Unknown error/)).toBeInTheDocument();
+  });
+
+  it('renders with zero values', () => {
+    mockUseAdminStats.mockReturnValue({
+      data: {
+        totalUsers: 0,
+        activeUsers: 0,
+        totalOrganizations: 0,
+        totalSessions: 0,
+      },
+      isLoading: false,
+      isError: false,
+      error: null,
+    } as any);
+
+    render(<DashboardStats />);
+
+    // Check all zeros are displayed
+    const zeroValues = screen.getAllByText('0');
+    expect(zeroValues.length).toBe(4); // 4 stat cards with 0 value
+  });
+
+  it('renders with dashboard-stats test id', () => {
+    mockUseAdminStats.mockReturnValue({
+      data: {
+        totalUsers: 100,
+        activeUsers: 80,
+        totalOrganizations: 20,
+        totalSessions: 30,
+      },
+      isLoading: false,
+      isError: false,
+      error: null,
+    } as any);
+
+    const { container } = render(<DashboardStats />);
+
+    const dashboardStats = container.querySelector('[data-testid="dashboard-stats"]');
+    expect(dashboardStats).toBeInTheDocument();
+    expect(dashboardStats).toHaveClass('grid', 'gap-4', 'md:grid-cols-2', 'lg:grid-cols-4');
+  });
+
+  it('renders icons with aria-hidden', () => {
+    mockUseAdminStats.mockReturnValue({
+      data: {
+        totalUsers: 100,
+        activeUsers: 80,
+        totalOrganizations: 20,
+        totalSessions: 30,
+      },
+      isLoading: false,
+      isError: false,
+      error: null,
+    } as any);
+
+    const { container } = render(<DashboardStats />);
+
+    // Check that icons have aria-hidden attribute
+    const icons = container.querySelectorAll('[aria-hidden="true"]');
+    expect(icons.length).toBeGreaterThan(0);
+  });
+});

frontend/tests/lib/api/hooks/useAdmin.test.tsx

@@ -0,0 +1,330 @@
+/**
+ * Tests for useAdmin hooks
+ * Verifies admin statistics and list fetching functionality
+ */
+
+import { renderHook, waitFor } from '@testing-library/react';
+import { QueryClient, QueryClientProvider } from '@tanstack/react-query';
+import { useAdminStats, useAdminUsers, useAdminOrganizations } from '@/lib/api/hooks/useAdmin';
+import { adminListUsers, adminListOrganizations } from '@/lib/api/client';
+import { useAuth } from '@/lib/auth/AuthContext';
+
+// Mock dependencies
+jest.mock('@/lib/api/client');
+jest.mock('@/lib/auth/AuthContext');
+
+const mockAdminListUsers = adminListUsers as jest.MockedFunction<typeof adminListUsers>;
+const mockAdminListOrganizations = adminListOrganizations as jest.MockedFunction<typeof adminListOrganizations>;
+const mockUseAuth = useAuth as jest.MockedFunction<typeof useAuth>;
+
+describe('useAdmin hooks', () => {
+  let queryClient: QueryClient;
+
+  beforeEach(() => {
+    queryClient = new QueryClient({
+      defaultOptions: {
+        queries: {
+          retry: false,
+        },
+      },
+    });
+    jest.clearAllMocks();
+  });
+
+  const wrapper = ({ children }: { children: React.ReactNode }) => (
+    <QueryClientProvider client={queryClient}>
+      {children}
+    </QueryClientProvider>
+  );
+
+  describe('useAdminStats', () => {
+    const mockUsersData = {
+      data: {
+        data: [
+          { is_active: true },
+          { is_active: true },
+          { is_active: false },
+        ],
+        pagination: { total: 3, page: 1, limit: 10000 },
+      },
+    };
+
+    const mockOrgsData = {
+      data: {
+        pagination: { total: 5 },
+      },
+    };
+
+    it('fetches and calculates stats when user is superuser', async () => {
+      mockUseAuth.mockReturnValue({
+        user: { is_superuser: true } as any,
+        isAuthenticated: true,
+        isLoading: false,
+        login: jest.fn(),
+        logout: jest.fn(),
+      });
+
+      mockAdminListUsers.mockResolvedValue(mockUsersData as any);
+      mockAdminListOrganizations.mockResolvedValue(mockOrgsData as any);
+
+      const { result } = renderHook(() => useAdminStats(), { wrapper });
+
+      await waitFor(() => expect(result.current.isSuccess).toBe(true));
+
+      expect(result.current.data).toEqual({
+        totalUsers: 3,
+        activeUsers: 2,
+        totalOrganizations: 5,
+        totalSessions: 0,
+      });
+
+      expect(mockAdminListUsers).toHaveBeenCalledWith({
+        query: { page: 1, limit: 10000 },
+        throwOnError: false,
+      });
+
+      expect(mockAdminListOrganizations).toHaveBeenCalledWith({
+        query: { page: 1, limit: 10000 },
+        throwOnError: false,
+      });
+    });
+
+    it('does not fetch when user is not superuser', async () => {
+      mockUseAuth.mockReturnValue({
+        user: { is_superuser: false } as any,
+        isAuthenticated: true,
+        isLoading: false,
+        login: jest.fn(),
+        logout: jest.fn(),
+      });
+
+      const { result } = renderHook(() => useAdminStats(), { wrapper });
+
+      expect(result.current.isLoading).toBe(false);
+      expect(result.current.data).toBeUndefined();
+      expect(mockAdminListUsers).not.toHaveBeenCalled();
+      expect(mockAdminListOrganizations).not.toHaveBeenCalled();
+    });
+
+    it('does not fetch when user is null', async () => {
+      mockUseAuth.mockReturnValue({
+        user: null,
+        isAuthenticated: false,
+        isLoading: false,
+        login: jest.fn(),
+        logout: jest.fn(),
+      });
+
+      const { result } = renderHook(() => useAdminStats(), { wrapper });
+
+      expect(result.current.isLoading).toBe(false);
+      expect(result.current.data).toBeUndefined();
+      expect(mockAdminListUsers).not.toHaveBeenCalled();
+    });
+
+    it('handles users API error', async () => {
+      mockUseAuth.mockReturnValue({
+        user: { is_superuser: true } as any,
+        isAuthenticated: true,
+        isLoading: false,
+        login: jest.fn(),
+        logout: jest.fn(),
+      });
+
+      mockAdminListUsers.mockResolvedValue({ error: 'Users fetch failed' } as any);
+
+      const { result } = renderHook(() => useAdminStats(), { wrapper });
+
+      await waitFor(() => expect(result.current.isError).toBe(true));
+      expect(result.current.error).toBeDefined();
+    });
+
+    it('handles organizations API error', async () => {
+      mockUseAuth.mockReturnValue({
+        user: { is_superuser: true } as any,
+        isAuthenticated: true,
+        isLoading: false,
+        login: jest.fn(),
+        logout: jest.fn(),
+      });
+
+      mockAdminListUsers.mockResolvedValue(mockUsersData as any);
+      mockAdminListOrganizations.mockResolvedValue({ error: 'Orgs fetch failed' } as any);
+
+      const { result } = renderHook(() => useAdminStats(), { wrapper });
+
+      await waitFor(() => expect(result.current.isError).toBe(true));
+      expect(result.current.error).toBeDefined();
+    });
+  });
+
+  describe('useAdminUsers', () => {
+    const mockResponse = {
+      data: {
+        data: [{ id: '1' }, { id: '2' }],
+        pagination: { total: 2, page: 1, limit: 50 },
+      },
+    };
+
+    it('fetches users when user is superuser', async () => {
+      mockUseAuth.mockReturnValue({
+        user: { is_superuser: true } as any,
+        isAuthenticated: true,
+        isLoading: false,
+        login: jest.fn(),
+        logout: jest.fn(),
+      });
+
+      mockAdminListUsers.mockResolvedValue(mockResponse as any);
+
+      const { result } = renderHook(() => useAdminUsers(), { wrapper });
+
+      await waitFor(() => expect(result.current.isSuccess).toBe(true));
+
+      expect(result.current.data).toEqual(mockResponse.data);
+      expect(mockAdminListUsers).toHaveBeenCalledWith({
+        query: { page: 1, limit: 50 },
+        throwOnError: false,
+      });
+    });
+
+    it('uses custom page and limit parameters', async () => {
+      mockUseAuth.mockReturnValue({
+        user: { is_superuser: true } as any,
+        isAuthenticated: true,
+        isLoading: false,
+        login: jest.fn(),
+        logout: jest.fn(),
+      });
+
+      mockAdminListUsers.mockResolvedValue(mockResponse as any);
+
+      renderHook(() => useAdminUsers(2, 100), { wrapper });
+
+      await waitFor(() => {
+        expect(mockAdminListUsers).toHaveBeenCalledWith({
+          query: { page: 2, limit: 100 },
+          throwOnError: false,
+        });
+      });
+    });
+
+    it('does not fetch when user is not superuser', async () => {
+      mockUseAuth.mockReturnValue({
+        user: { is_superuser: false } as any,
+        isAuthenticated: true,
+        isLoading: false,
+        login: jest.fn(),
+        logout: jest.fn(),
+      });
+
+      const { result } = renderHook(() => useAdminUsers(), { wrapper });
+
+      expect(result.current.isLoading).toBe(false);
+      expect(result.current.data).toBeUndefined();
+      expect(mockAdminListUsers).not.toHaveBeenCalled();
+    });
+
+    it('handles API error', async () => {
+      mockUseAuth.mockReturnValue({
+        user: { is_superuser: true } as any,
+        isAuthenticated: true,
+        isLoading: false,
+        login: jest.fn(),
+        logout: jest.fn(),
+      });
+
+      mockAdminListUsers.mockResolvedValue({ error: 'Fetch failed' } as any);
+
+      const { result } = renderHook(() => useAdminUsers(), { wrapper });
+
+      await waitFor(() => expect(result.current.isError).toBe(true));
+      expect(result.current.error).toBeDefined();
+    });
+  });
+
+  describe('useAdminOrganizations', () => {
+    const mockResponse = {
+      data: {
+        data: [{ id: '1' }, { id: '2' }],
+        pagination: { total: 2, page: 1, limit: 50 },
+      },
+    };
+
+    it('fetches organizations when user is superuser', async () => {
+      mockUseAuth.mockReturnValue({
+        user: { is_superuser: true } as any,
+        isAuthenticated: true,
+        isLoading: false,
+        login: jest.fn(),
+        logout: jest.fn(),
+      });
+
+      mockAdminListOrganizations.mockResolvedValue(mockResponse as any);
+
+      const { result } = renderHook(() => useAdminOrganizations(), { wrapper });
+
+      await waitFor(() => expect(result.current.isSuccess).toBe(true));
+
+      expect(result.current.data).toEqual(mockResponse.data);
+      expect(mockAdminListOrganizations).toHaveBeenCalledWith({
+        query: { page: 1, limit: 50 },
+        throwOnError: false,
+      });
+    });
+
+    it('uses custom page and limit parameters', async () => {
+      mockUseAuth.mockReturnValue({
+        user: { is_superuser: true } as any,
+        isAuthenticated: true,
+        isLoading: false,
+        login: jest.fn(),
+        logout: jest.fn(),
+      });
+
+      mockAdminListOrganizations.mockResolvedValue(mockResponse as any);
+
+      renderHook(() => useAdminOrganizations(3, 25), { wrapper });
+
+      await waitFor(() => {
+        expect(mockAdminListOrganizations).toHaveBeenCalledWith({
+          query: { page: 3, limit: 25 },
+          throwOnError: false,
+        });
+      });
+    });
+
+    it('does not fetch when user is not superuser', async () => {
+      mockUseAuth.mockReturnValue({
+        user: { is_superuser: false } as any,
+        isAuthenticated: true,
+        isLoading: false,
+        login: jest.fn(),
+        logout: jest.fn(),
+      });
+
+      const { result } = renderHook(() => useAdminOrganizations(), { wrapper });
+
+      expect(result.current.isLoading).toBe(false);
+      expect(result.current.data).toBeUndefined();
+      expect(mockAdminListOrganizations).not.toHaveBeenCalled();
+    });
+
+    it('handles API error', async () => {
+      mockUseAuth.mockReturnValue({
+        user: { is_superuser: true } as any,
+        isAuthenticated: true,
+        isLoading: false,
+        login: jest.fn(),
+        logout: jest.fn(),
+      });
+
+      mockAdminListOrganizations.mockResolvedValue({ error: 'Fetch failed' } as any);
+
+      const { result } = renderHook(() => useAdminOrganizations(), { wrapper });
+
+      await waitFor(() => expect(result.current.isError).toBe(true));
+      expect(result.current.error).toBeDefined();
+    });
+  });
+});