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# Testing & Mocks
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Mock implementations and testing utilities for developing and testing Tauri applications without requiring the full Tauri runtime environment.
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## Capabilities
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### IPC Mocking
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Mock the core IPC (Inter-Process Communication) system to simulate backend responses during testing.
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```typescript { .api }
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/**
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 * Mock the IPC system with custom command handlers
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 * @param cb - Function to handle mocked IPC commands
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 * @param options - Optional configuration for mocking behavior  
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 */
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function mockIPC(
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  cb: (cmd: string, payload?: InvokeArgs) => unknown, 
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  options?: MockIPCOptions
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): void;
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interface MockIPCOptions {
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  /** Whether to mock event system as well */
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  shouldMockEvents?: boolean;
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}
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type InvokeArgs = Record<string, unknown> | number[] | ArrayBuffer | Uint8Array;
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```
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### Window Mocking
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Mock window instances and labels for testing window-related functionality.
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```typescript { .api }
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/**
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 * Mock window instances for testing
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 * @param current - Label of the current window
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 * @param additionalWindows - Labels of additional windows to mock
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 */
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function mockWindows(current: string, ...additionalWindows: string[]): void;
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```
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### File Source Conversion Mocking
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Mock file path to URL conversion for testing asset loading.
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```typescript { .api }
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/**
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 * Mock file source conversion for testing
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 * @param osName - Operating system name to simulate ('linux', 'darwin', 'windows')
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 */
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function mockConvertFileSrc(osName: string): void;
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```
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### Mock Cleanup
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Clear all active mocks and restore normal Tauri behavior.
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```typescript { .api }
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/**
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 * Clear all mocks and restore normal Tauri functionality
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 */
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function clearMocks(): void;
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```
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## Usage Examples
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### Basic IPC Mocking
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```typescript
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import { mockIPC, invoke } from '@tauri-apps/api/core';
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import { clearMocks } from '@tauri-apps/api/mocks';
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// Mock IPC commands for testing
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mockIPC((cmd, args) => {
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  switch (cmd) {
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    case 'get_user_data':
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      return { name: 'Test User', email: 'test@example.com' };
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    case 'save_file':
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      console.log('Mock: Saving file', args);
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      return { success: true, path: '/mock/path/file.txt' };
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    case 'calculate':
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      const { a, b } = args as { a: number; b: number };
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      return { result: a + b };
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    default:
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      throw new Error(`Unknown command: ${cmd}`);
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  }
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});
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// Test the application code
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async function testUserData() {
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  const userData = await invoke('get_user_data');
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  console.log('User data:', userData); // { name: 'Test User', email: 'test@example.com' }
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  const saveResult = await invoke('save_file', { content: 'Hello', filename: 'test.txt' });
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  console.log('Save result:', saveResult); // { success: true, path: '/mock/path/file.txt' }
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  const calcResult = await invoke('calculate', { a: 5, b: 3 });
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  console.log('Calculation:', calcResult); // { result: 8 }
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}
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await testUserData();
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// Clean up mocks
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clearMocks();
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```
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### Testing with Mock Events
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```typescript
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import { mockIPC } from '@tauri-apps/api/mocks';
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import { listen, emit } from '@tauri-apps/api/event';
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// Mock IPC with events enabled
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mockIPC((cmd, args) => {
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  if (cmd === 'start_background_task') {
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    // Simulate background task that emits progress events
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    setTimeout(() => emit('task-progress', { progress: 0.5 }), 100);
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    setTimeout(() => emit('task-complete', { result: 'done' }), 200);
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    return { taskId: 'mock-task-123' };
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  }
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  return null;
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}, { shouldMockEvents: true });
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// Test event-driven functionality
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async function testBackgroundTask() {
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  // Set up event listeners
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  const progressListener = await listen('task-progress', (event) => {
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    console.log('Progress:', event.payload.progress);
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  });
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  const completeListener = await listen('task-complete', (event) => {
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    console.log('Task complete:', event.payload.result);
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    progressListener(); // Clean up listener
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    completeListener();
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  });
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  // Start the task
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  const result = await invoke('start_background_task', { data: 'test' });
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  console.log('Task started:', result);
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}
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await testBackgroundTask();
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clearMocks();
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```
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### Window Mocking for Testing
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```typescript
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import { mockWindows } from '@tauri-apps/api/mocks';
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import { getCurrentWindow, Window } from '@tauri-apps/api/window';
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// Mock multiple windows
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mockWindows('main-window', 'settings-window', 'about-window');
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async function testWindowFunctionality() {
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  // Get current window (will be 'main-window')
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  const currentWindow = getCurrentWindow();
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  console.log('Current window label:', currentWindow.label); // 'main-window'
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  // Get all windows
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  const allWindows = await Window.getAll();
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  console.log('All windows:', allWindows.map(w => w.label)); 
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  // ['main-window', 'settings-window', 'about-window']
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  // Get specific window
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  const settingsWindow = await Window.getByLabel('settings-window');
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  console.log('Settings window found:', settingsWindow !== null); // true
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  // Test window operations (these will be no-ops in mock)
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  await currentWindow.setTitle('Test Title');
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  await currentWindow.setSize({ width: 800, height: 600 });
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}
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await testWindowFunctionality();
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clearMocks();
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```
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### File Source Mocking
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```typescript
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import { mockConvertFileSrc } from '@tauri-apps/api/mocks';
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import { convertFileSrc } from '@tauri-apps/api/core';
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// Mock file conversion for different platforms
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mockConvertFileSrc('linux');
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function testFileConversion() {
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  const linuxPath = convertFileSrc('/home/user/image.png');
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  console.log('Linux path:', linuxPath); // Mock Linux-style conversion
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  clearMocks();
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  mockConvertFileSrc('windows');
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  const windowsPath = convertFileSrc('C:\\Users\\User\\image.png');
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  console.log('Windows path:', windowsPath); // Mock Windows-style conversion
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  clearMocks();
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  mockConvertFileSrc('darwin');
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  const macPath = convertFileSrc('/Users/user/image.png');
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  console.log('macOS path:', macPath); // Mock macOS-style conversion
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}
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testFileConversion();
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clearMocks();
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```
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### Jest Testing Integration
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```typescript
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// test-utils.ts
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import { mockIPC, mockWindows, clearMocks } from '@tauri-apps/api/mocks';
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export function setupTauriMocks() {
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  // Mock basic IPC commands
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  mockIPC((cmd, args) => {
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    switch (cmd) {
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      case 'get_config':
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        return { theme: 'dark', language: 'en' };
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      case 'set_config':
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        return { success: true };
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      case 'get_version':
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        return '1.0.0';
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      default:
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        return null;
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    }
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  });
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  // Mock windows
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  mockWindows('main');
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}
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export function teardownTauriMocks() {
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  clearMocks();
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}
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// app.test.ts
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import { setupTauriMocks, teardownTauriMocks } from './test-utils';
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import { invoke } from '@tauri-apps/api/core';
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describe('Application Tests', () => {
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  beforeEach(() => {
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    setupTauriMocks();
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  });
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  afterEach(() => {
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    teardownTauriMocks();
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  });
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  test('should load configuration', async () => {
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    const config = await invoke('get_config');
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    expect(config).toEqual({ theme: 'dark', language: 'en' });
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  });
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  test('should save configuration', async () => {
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    const result = await invoke('set_config', { theme: 'light' });
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    expect(result).toEqual({ success: true });
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  });
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  test('should get version', async () => {
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    const version = await invoke('get_version');
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    expect(version).toBe('1.0.0');
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  });
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});
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```
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### Advanced Mock Scenarios
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```typescript
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import { mockIPC } from '@tauri-apps/api/mocks';
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// Mock complex async operations
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mockIPC(async (cmd, args) => {
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  switch (cmd) {
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    case 'fetch_data':
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      // Simulate network delay
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      await new Promise(resolve => setTimeout(resolve, 100));
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      return { data: ['item1', 'item2', 'item3'] };
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    case 'upload_file':
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      // Simulate file upload with progress
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      const { file } = args as { file: string };
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      await new Promise(resolve => setTimeout(resolve, 50));
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      return { 
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        success: true, 
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        url: `https://example.com/files/${file}`,
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        size: 1024 
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      };
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    case 'database_query':
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      // Simulate database operations
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      const { query } = args as { query: string };
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      if (query.includes('SELECT')) {
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        return { rows: [{ id: 1, name: 'Test' }] };
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      } else if (query.includes('INSERT')) {
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        return { insertedId: 42 };
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      }
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      throw new Error('Invalid query');
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    default:
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      throw new Error(`Command not mocked: ${cmd}`);
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  }
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});
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// Test error scenarios
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async function testErrorHandling() {
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  try {
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    await invoke('invalid_command');
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  } catch (error) {
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    console.log('Expected error:', error.message); // "Command not mocked: invalid_command"
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  }
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  try {
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    await invoke('database_query', { query: 'DROP TABLE users' });
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  } catch (error) {
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    console.log('Database error:', error.message); // "Invalid query"
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  }
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}
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await testErrorHandling();
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```
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### Mock State Management
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```typescript
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import { mockIPC } from '@tauri-apps/api/mocks';
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// Create stateful mocks
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class MockDatabase {
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  private data: Record<string, any> = {};
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  get(key: string) {
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    return this.data[key] || null;
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  }
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  set(key: string, value: any) {
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    this.data[key] = value;
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    return { success: true };
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  }
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  list() {
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    return Object.keys(this.data);
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  }
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  clear() {
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    this.data = {};
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    return { success: true };
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  }
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}
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const mockDb = new MockDatabase();
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mockIPC((cmd, args) => {
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  switch (cmd) {
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    case 'db_get':
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      const { key } = args as { key: string };
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      return mockDb.get(key);
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    case 'db_set':
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      const { key: setKey, value } = args as { key: string; value: any };
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      return mockDb.set(setKey, value);
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    case 'db_list':
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      return mockDb.list();
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    case 'db_clear':
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      return mockDb.clear();
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    default:
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      return null;
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  }
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});
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// Test stateful operations
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async function testStatefulMocks() {
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  // Set some data
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  await invoke('db_set', { key: 'user:1', value: { name: 'Alice' } });
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  await invoke('db_set', { key: 'user:2', value: { name: 'Bob' } });
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  // Retrieve data
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  const user1 = await invoke('db_get', { key: 'user:1' });
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  console.log('User 1:', user1); // { name: 'Alice' }
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  // List keys
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  const keys = await invoke('db_list');
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  console.log('Keys:', keys); // ['user:1', 'user:2']
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  // Clear all data
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  await invoke('db_clear');
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  const keysAfterClear = await invoke('db_list');
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  console.log('Keys after clear:', keysAfterClear); // []
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}
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await testStatefulMocks();
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```
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### Testing Best Practices
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```typescript
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import { mockIPC, mockWindows, clearMocks } from '@tauri-apps/api/mocks';
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// Utility for consistent mock setup
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export class TauriTestEnvironment {
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  private mockHandlers = new Map<string, Function>();
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  mockCommand(cmd: string, handler: Function) {
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    this.mockHandlers.set(cmd, handler);
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  }
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  setup() {
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    mockIPC((cmd, args) => {
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      const handler = this.mockHandlers.get(cmd);
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      if (handler) {
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        return handler(args);
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      }
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      throw new Error(`Unmocked command: ${cmd}`);
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    });
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    mockWindows('main-window');
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  }
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  teardown() {
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    clearMocks();
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    this.mockHandlers.clear();
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  }
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}
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// Usage in tests
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describe('Feature Tests', () => {
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  let testEnv: TauriTestEnvironment;
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  beforeEach(() => {
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    testEnv = new TauriTestEnvironment();
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    // Set up common mocks
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    testEnv.mockCommand('get_config', () => ({ theme: 'light' }));
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    testEnv.mockCommand('save_config', () => ({ success: true }));
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    testEnv.setup();
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  });
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  afterEach(() => {
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    testEnv.teardown();
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  });
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  test('feature specific test', async () => {
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    // Add feature-specific mocks
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    testEnv.mockCommand('feature_command', (args) => {
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      return { result: `processed ${args.input}` };
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    });
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    // Test the feature
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    const result = await invoke('feature_command', { input: 'test' });
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    expect(result.result).toBe('processed test');
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  });
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});
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```
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## Mock Limitations
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The mocking system has some limitations to be aware of:
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- **Window operations**: Mocked windows don't actually create system windows
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- **File system**: File operations still need proper mocking at the command level
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- **Platform APIs**: Platform-specific features may not be fully mockable
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- **Event timing**: Event emission timing is simplified in mocks
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- **Resource management**: Mocked resources don't have the same lifecycle as real ones
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For comprehensive testing, combine Tauri mocks with other testing tools and consider running integration tests with the actual Tauri runtime when possible.