MCP Image Extractor

import { jest } from '@jest/globals'; import * as fs from 'fs'; import * as path from 'path'; import sharp from 'sharp'; import { extractImageFromFile } from '../src/image-utils'; // Mock dependencies to run in isolation jest.mock('fs'); jest.mock('path'); jest.mock('sharp'); // Mock console.warn and error beforeEach(() => { jest.spyOn(console, 'warn').mockImplementation(() => {}); jest.spyOn(console, 'error').mockImplementation(() => {}); }); afterEach(() => { jest.restoreAllMocks(); }); // Define mock types type MockedSharp = { metadata: jest.Mock; resize: jest.Mock; toBuffer: jest.Mock; jpeg: jest.Mock; png: jest.Mock; webp: jest.Mock; avif: jest.Mock; tiff: jest.Mock; }; describe('Image Compression', () => { // Sample image buffer for testing const testImageBuffer = Buffer.from('test-image-data'); const originalSize = testImageBuffer.length; beforeEach(() => { // Clear all mocks before each test jest.clearAllMocks(); // Mock file system (fs.existsSync as jest.Mock).mockReturnValue(true); (fs.readFileSync as jest.Mock).mockReturnValue(testImageBuffer); (fs.statSync as jest.Mock).mockReturnValue({ size: originalSize }); // Path mock (path.extname as jest.Mock).mockReturnValue('.png'); (path.basename as jest.Mock).mockImplementation(function(p: unknown, ext?: unknown) { return String(p).replace(String(ext || ''), ''); }); // Create compressed buffer that's smaller than the original const compressedBuffer = Buffer.from('compressed'); // Create a mock sharp instance with properly typed methods const mockSharpInstance: MockedSharp = { // @ts-ignore - Ignore type error for mockResolvedValue metadata: jest.fn().mockResolvedValue({ width: 800, height: 600, format: 'png' }), resize: jest.fn().mockReturnThis(), // @ts-ignore - Ignore type error for mockResolvedValue toBuffer: jest.fn().mockResolvedValue(compressedBuffer), jpeg: jest.fn().mockReturnThis(), png: jest.fn().mockReturnThis(), webp: jest.fn().mockReturnThis(), avif: jest.fn().mockReturnThis(), tiff: jest.fn().mockReturnThis(), }; ((sharp as unknown) as jest.Mock).mockImplementation(() => mockSharpInstance); }); it('should compress PNG images', async () => { (path.extname as jest.Mock).mockReturnValue('.png'); const result = await extractImageFromFile({ file_path: 'test_image.png', resize: true, max_width: 512, max_height: 512 }); expect(result.content).toBeDefined(); expect(result.content.length).toBeGreaterThan(0); // Get the metadata from the result const metadata = JSON.parse(result.content[0].text as string); // Since our compressed buffer is smaller than the original, size should be reduced expect(metadata.size).toBeLessThan(originalSize); // Check if the PNG compression method was called const sharpInstance = (sharp as unknown as jest.Mock).mock.results[0].value as MockedSharp; expect(sharpInstance.png).toHaveBeenCalled(); }); it('should compress JPEG images', async () => { (path.extname as jest.Mock).mockReturnValue('.jpg'); const result = await extractImageFromFile({ file_path: 'test_image.jpg', resize: true, max_width: 512, max_height: 512 }); expect(result.content).toBeDefined(); expect(result.content.length).toBeGreaterThan(0); // Get the metadata from the result const metadata = JSON.parse(result.content[0].text as string); // Check if the JPEG compression method was called const sharpInstance = (sharp as unknown as jest.Mock).mock.results[0].value as MockedSharp; expect(sharpInstance.jpeg).toHaveBeenCalled(); }); it('should handle unsupported formats gracefully', async () => { // Mock sharp instance to throw on compression const mockErrorSharpInstance: MockedSharp = { // @ts-ignore metadata: jest.fn().mockResolvedValue({ width: 800, height: 600, format: 'unknown' }), resize: jest.fn().mockReturnThis(), // @ts-ignore toBuffer: jest.fn().mockResolvedValue(testImageBuffer), jpeg: jest.fn().mockImplementation(() => { throw new Error('Unsupported format'); }), png: jest.fn().mockImplementation(() => { throw new Error('Unsupported format'); }), webp: jest.fn().mockImplementation(() => { throw new Error('Unsupported format'); }), avif: jest.fn().mockImplementation(() => { throw new Error('Unsupported format'); }), tiff: jest.fn().mockImplementation(() => { throw new Error('Unsupported format'); }), }; ((sharp as unknown) as jest.Mock).mockImplementation(() => mockErrorSharpInstance); (path.extname as jest.Mock).mockReturnValue('.unknown'); const result = await extractImageFromFile({ file_path: 'test_image.unknown', resize: true, max_width: 512, max_height: 512 }); // The function should still return a result even if compression fails expect(result.content).toBeDefined(); expect(result.content.length).toBeGreaterThan(0); // Check that console.warn was called expect(console.warn).toHaveBeenCalled(); }); });