Testing and mocking

Wrap the small public API behind an application service when tests need stable fixtures. Mock the package at the module boundary rather than importing its internal native module.

import { vi } from 'vitest';

vi.mock('react-native-image-compression-kit', () => ({
  getImageCompressionCapabilities: vi.fn().mockResolvedValue({
    platform: 'android',
    formats: [
      {
        format: 'jpeg',
        input: true,
        output: true,
        supportsAlpha: false,
        supportsAnimation: false,
      },
    ],
    metadataPolicies: ['preserve', 'safe', 'strip'],
    supportsTargetSizeCompression: true,
    supportsCancellation: true,
    maxConcurrentOperations: 2,
    supportsDecodeDownsampling: true,
    resourceLimits: {
      maxSourceDimension: 32_768,
      maxSourcePixels: 100_000_000,
      maxWorkingPixels: 25_000_000,
    },
  }),
  compressImage: vi.fn().mockResolvedValue({
    uri: 'file:///tmp/result.jpg',
    format: 'jpeg',
    width: 1200,
    height: 800,
    byteSize: 240000,
    originalByteSize: 1200000,
    compressionRatio: 0.2,
  }),
}));

Keep at least one real native integration lane for URI access, codec capabilities, metadata, and output-file behavior. JavaScript mocks cannot prove those contracts.