Replace crypto tests with comprehensive unit tests for authStore, storage, and configuration modules

- Removed outdated `crypto` tests; added dedicated and structured tests for `authStore`, `storage`, and `app.config`.
- Enhanced test coverage for user and token validation, secure persistence, state management, and configuration parsing.
- Consolidated encryption and storage error handling with thorough validation to ensure SSR-safety and resilience.
- Improved runtime validations for tokens and configuration with stricter type checks and fallback mechanisms.

frontend/tests/config/app.config.test.ts

@@ -0,0 +1,151 @@
+/**
+ * Tests for application configuration
+ */
+
+describe('App Configuration', () => {
+  let originalEnv: NodeJS.ProcessEnv;
+
+  beforeEach(() => {
+    // Save original env
+    originalEnv = { ...process.env };
+
+    // Clear module cache to test with different env vars
+    jest.resetModules();
+  });
+
+  afterEach(() => {
+    // Restore original env
+    process.env = originalEnv;
+  });
+
+  describe('parseIntSafe', () => {
+    it('should parse valid integers', () => {
+      process.env.NEXT_PUBLIC_API_TIMEOUT = '5000';
+
+      // Dynamically import to pick up new env
+      const { config } = require('@/config/app.config');
+
+      expect(config.api.timeout).toBe(5000);
+    });
+
+    it('should use default for NaN', () => {
+      process.env.NEXT_PUBLIC_API_TIMEOUT = 'not_a_number';
+
+      const { config } = require('@/config/app.config');
+
+      expect(config.api.timeout).toBe(30000); // default
+    });
+
+    it('should enforce minimum values', () => {
+      process.env.NEXT_PUBLIC_API_TIMEOUT = '500'; // Below min of 1000
+
+      const { config } = require('@/config/app.config');
+
+      expect(config.api.timeout).toBe(1000); // minimum
+    });
+
+    it('should enforce maximum values', () => {
+      process.env.NEXT_PUBLIC_API_TIMEOUT = '999999'; // Above max of 120000
+
+      const { config } = require('@/config/app.config');
+
+      expect(config.api.timeout).toBe(120000); // maximum
+    });
+
+    it('should handle negative numbers', () => {
+      process.env.NEXT_PUBLIC_ACCESS_TOKEN_EXPIRY = '-100';
+
+      const { config } = require('@/config/app.config');
+
+      expect(config.auth.accessTokenExpiry).toBe(60000); // minimum
+    });
+  });
+
+  describe('URL validation', () => {
+    it('should accept valid URLs', () => {
+      process.env.NEXT_PUBLIC_API_BASE_URL = 'https://api.example.com';
+
+      const { config } = require('@/config/app.config');
+
+      expect(config.api.baseUrl).toBe('https://api.example.com');
+    });
+
+    it('should throw on invalid URLs', () => {
+      process.env.NEXT_PUBLIC_API_BASE_URL = 'not a url';
+
+      // Mock window to undefined to prevent validation
+      const originalWindow = global.window;
+      (global as any).window = undefined;
+
+      expect(() => {
+        require('@/config/app.config');
+      }).toThrow('Invalid URL');
+
+      (global as any).window = originalWindow;
+    });
+  });
+
+  describe('Config validation', () => {
+    it('should validate access token expiry is positive', () => {
+      process.env.NEXT_PUBLIC_ACCESS_TOKEN_EXPIRY = '-1000';
+
+      const originalWindow = global.window;
+      (global as any).window = { document: {} }; // Simulate browser
+
+      expect(() => {
+        require('@/config/app.config');
+      }).toThrow('Invalid application configuration');
+
+      (global as any).window = originalWindow;
+    });
+
+    it('should validate refresh token expiry > access token expiry', () => {
+      process.env.NEXT_PUBLIC_ACCESS_TOKEN_EXPIRY = '1000000';
+      process.env.NEXT_PUBLIC_REFRESH_TOKEN_EXPIRY = '500000'; // Less than access!
+
+      const originalWindow = global.window;
+      (global as any).window = { document: {} };
+
+      expect(() => {
+        require('@/config/app.config');
+      }).toThrow('Invalid application configuration');
+
+      (global as any).window = originalWindow;
+    });
+  });
+
+  describe('Boolean parsing', () => {
+    it('should parse "true" as true', () => {
+      process.env.NEXT_PUBLIC_ENABLE_REGISTRATION = 'true';
+
+      const { config } = require('@/config/app.config');
+
+      expect(config.features.enableRegistration).toBe(true);
+    });
+
+    it('should parse anything else as false', () => {
+      process.env.NEXT_PUBLIC_ENABLE_REGISTRATION = 'yes';
+
+      const { config } = require('@/config/app.config');
+
+      expect(config.features.enableRegistration).toBe(false);
+    });
+
+    it('should use default when undefined', () => {
+      delete process.env.NEXT_PUBLIC_ENABLE_REGISTRATION;
+
+      const { config } = require('@/config/app.config');
+
+      expect(config.features.enableRegistration).toBe(true); // default
+    });
+  });
+
+  describe('Environment detection', () => {
+    it('should detect test environment', () => {
+      // NODE_ENV is set by Jest to 'test'
+      const { config } = require('@/config/app.config');
+
+      expect(config.env.isTest).toBe(true);
+    });
+  });
+});