MCP Image Extractor

import { describe, it, expect, beforeEach, jest } from '@jest/globals'; import axios from 'axios'; import sharp from 'sharp'; import { extractImageFromUrl } from '../src/image-utils'; // Mock dependencies jest.mock('axios'); jest.mock('sharp'); // Mock console functions 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; }; describe('URL Image Extraction Tests', () => { const testImageBuffer = Buffer.from('test-image-data'); beforeEach(() => { // Clear all mocks before each test jest.clearAllMocks(); // Create a mock response with image data (axios.get as jest.Mock).mockResolvedValue({ data: testImageBuffer, headers: { 'content-type': 'image/png' } } as any); // 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(), }; ((sharp as unknown) as jest.Mock).mockImplementation(() => mockSharpInstance); // Mock axios to throw a network error (axios.get as jest.Mock).mockRejectedValue(new Error('Network error') as never); // Mock a large image buffer const largeImageBuffer = Buffer.alloc(1000, 'x'); (axios.get as jest.Mock).mockResolvedValue({ data: largeImageBuffer, headers: { 'content-type': 'image/jpeg' } } as any); }); it('validates URL format', async () => { const result = await extractImageFromUrl({ url: 'invalid-url', resize: true, max_width: 800, max_height: 800 }); expect(result.isError).toBe(true); expect(result.content[0].text).toContain('Error: URL must start with http://'); }); it('successfully processes valid URLs', async () => { const result = await extractImageFromUrl({ url: 'https://example.com/image.png', resize: true, max_width: 800, max_height: 800 }); // Validate the result expect(result.isError).toBeUndefined(); expect(result.content).toHaveLength(2); // Validate metadata const metadata = JSON.parse(result.content[0].text as string); expect(metadata.width).toBeDefined(); expect(metadata.height).toBeDefined(); expect(metadata.format).toBeDefined(); expect(metadata.size).toBeDefined(); // Validate image data expect(result.content[1].type).toBe('image'); expect(result.content[1].data).toBeDefined(); expect(result.content[1].mimeType).toBe('image/png'); // Verify axios was called with the right params expect(axios.get).toHaveBeenCalledWith('https://example.com/image.png', expect.objectContaining({ responseType: 'arraybuffer' }) ); }); it('handles network errors', async () => { const result = await extractImageFromUrl({ url: 'https://example.com/image.png', resize: true, max_width: 800, max_height: 800 }); expect(result.isError).toBe(true); expect(result.content[0].text).toContain('Error: Network error'); }); it('compresses images from URLs', async () => { const result = await extractImageFromUrl({ url: 'https://example.com/large-image.jpg', resize: true, max_width: 800, max_height: 800 }); // Get the metadata from the result const metadata = JSON.parse(result.content[0].text as string); // Verify size was reduced expect(metadata.size).toBe(compressedBuffer.length); expect(metadata.size).toBeLessThan(largeImageBuffer.length); // Verify jpeg compression was used for jpeg image const sharpInstance = (sharp as unknown as jest.Mock).mock.results[0].value as MockedSharp; expect(sharpInstance.jpeg).toHaveBeenCalled(); }); });