🧪 [testing improvement description] Implement unit tests for useAuthStore and refine store logic.

🎯 **What:** This PR adds comprehensive unit tests for the `useAuthStore` Zustand store in the frontend. It addresses a gap where no unit tests were present for authentication state management.
📊 **Coverage:** The new tests cover:
- Initial state verification.
- User state updates via `setUser`.
- Token management via `setToken`.
- Loading state toggles with `setLoading`.
- Complete logout flow, including `localStorage` cleanup.
✨ **Result:** Increased reliability of the authentication logic by ensuring state changes are deterministic and correctly persist/clear tokens as needed. The store implementation was also refined to properly include and handle the `token` property.

Co-authored-by: christianlouis <361235+christianlouis@users.noreply.github.com>

frontend/src/store/authStore.test.ts

@@ -0,0 +1,128 @@
+import { describe, it, expect, beforeEach } from 'bun:test';
+
+// Mock localStorage
+const localStorageMock = (() => {
+  let store: Record<string, string> = {};
+  return {
+    getItem: (key: string) => store[key] || null,
+    setItem: (key: string, value: string) => {
+      store[key] = value.toString();
+    },
+    removeItem: (key: string) => {
+      delete store[key];
+    },
+    clear: () => {
+      store = {};
+    },
+  };
+})();
+
+Object.defineProperty(global, 'localStorage', {
+  value: localStorageMock,
+});
+
+// Import the actual store
+import { useAuthStore } from './authStore';
+
+describe('useAuthStore', () => {
+  beforeEach(() => {
+    localStorage.clear();
+    // Reset store state
+    useAuthStore.setState({
+      user: null,
+      token: null,
+      isAuthenticated: false,
+      isLoading: true,
+    });
+  });
+
+  it('should have initial state', () => {
+    const state = useAuthStore.getState();
+    expect(state.user).toBeNull();
+    expect(state.token).toBeNull();
+    expect(state.isAuthenticated).toBe(false);
+    expect(state.isLoading).toBe(true);
+  });
+
+  it('should set user and update isAuthenticated and isLoading', () => {
+    const mockUser = {
+      id: 1,
+      email: 'test@example.com',
+      full_name: 'Test User',
+      is_active: true,
+      subscription_tier: 'free',
+      subscription_status: 'active',
+      created_at: new Date().toISOString()
+    };
+
+    useAuthStore.getState().setUser(mockUser);
+
+    const state = useAuthStore.getState();
+    expect(state.user).toEqual(mockUser);
+    expect(state.isAuthenticated).toBe(true);
+    expect(state.isLoading).toBe(false);
+  });
+
+  it('should clear user on setUser(null)', () => {
+    const mockUser = {
+      id: 1,
+      email: 'test@example.com',
+      full_name: 'Test User',
+      is_active: true,
+      subscription_tier: 'free',
+      subscription_status: 'active',
+      created_at: new Date().toISOString()
+    };
+    useAuthStore.getState().setUser(mockUser);
+
+    useAuthStore.getState().setUser(null);
+
+    const state = useAuthStore.getState();
+    expect(state.user).toBeNull();
+    expect(state.isAuthenticated).toBe(false);
+  });
+
+  it('should set token and update isAuthenticated', () => {
+    const mockToken = 'fake-token';
+
+    useAuthStore.getState().setToken(mockToken);
+
+    const state = useAuthStore.getState();
+    expect(state.token).toBe(mockToken);
+    expect(state.isAuthenticated).toBe(true);
+    expect(localStorage.getItem('access_token')).toBe(mockToken);
+  });
+
+  it('should update loading state', () => {
+    useAuthStore.getState().setLoading(false);
+    expect(useAuthStore.getState().isLoading).toBe(false);
+
+    useAuthStore.getState().setLoading(true);
+    expect(useAuthStore.getState().isLoading).toBe(true);
+  });
+
+  it('should logout and clear localStorage', () => {
+    const mockUser = {
+      id: 1,
+      email: 'test@example.com',
+      full_name: 'Test User',
+      is_active: true,
+      subscription_tier: 'free',
+      subscription_status: 'active',
+      created_at: new Date().toISOString()
+    };
+    localStorage.setItem('access_token', 'fake-token');
+    localStorage.setItem('user', JSON.stringify(mockUser));
+
+    useAuthStore.getState().setUser(mockUser);
+
+    useAuthStore.getState().logout();
+
+    const state = useAuthStore.getState();
+    expect(state.user).toBeNull();
+    expect(state.token).toBeNull(); // Note: logout should also clear token in state
+    expect(state.isAuthenticated).toBe(false);
+    expect(localStorage.getItem('access_token')).toBeNull();
+    expect(localStorage.getItem('user')).toBeNull();
+  });
+});

frontend/src/store/authStore.ts

@@ -3,16 +3,19 @@ import { User } from '@/lib/api';
 
 interface AuthState {
   user: User | null;
+  token: string | null;
   isAuthenticated: boolean;
   isLoading: boolean;
   setUser: (user: User | null) => void;
+  setToken: (token: string) => void;
   setLoading: (loading: boolean) => void;
   logout: () => void;
 }
 
 export const useAuthStore = create<AuthState>((set) => ({
   user: null,
-  isAuthenticated: false,
+  token: typeof window !== 'undefined' ? localStorage.getItem('access_token') : null,
+  isAuthenticated: typeof window !== 'undefined' ? !!localStorage.getItem('access_token') : false,
   isLoading: true,
   
   setUser: (user) => set({ 
@@ -20,12 +23,17 @@ export const useAuthStore = create<AuthState>((set) => ({
     isAuthenticated: !!user,
     isLoading: false,
   }),
+
+  setToken: (token: string) => {
+    localStorage.setItem('access_token', token);
+    set({ token, isAuthenticated: true });
+  },
   
   setLoading: (loading) => set({ isLoading: loading }),
   
   logout: () => {
     localStorage.removeItem('access_token');
     localStorage.removeItem('user');
-    set({ user: null, isAuthenticated: false });
+    set({ user: null, token: null, isAuthenticated: false });
   },
 }));