imghash-bbassi/test/index.spec.js

Image perceptual hash calculation for node. Based on package imghash v0.0.7 but fixes that is waiting to go upstream.

const fs = require('fs');
const leven = require('leven');

const imghash = require('../index');

it.each([
  ['jpeg', '/files/absolut1'],
  ['png', '/files/castle1.png'],
  ['bmp', '/files/castle1.bmp']
])('should create hash for %s', async (fileType, filePath) => {
  const hash = await imghash.hash(__dirname + filePath)
  expect(hash).toBeDefined()
})

it('should create close hashes for the same image but in a different format', async () => {
  const h1 = await imghash.hash(__dirname + '/files/castle1.png');
  const h2 = await imghash.hash(__dirname + '/files/castle1.bmp');
  const dist = leven(h1, h2);
  expect(dist).toBeLessThan(12);
});

it('should create same hashes the same images', async () => {
  const h1 = await imghash.hash(__dirname + '/files/castle1.png');
  const h2 = await imghash.hash(__dirname + '/files/castle2.png');
  expect(h1).toBe(h2);
});

it('should create different hashes different images', async () => {
  const h1 = await imghash.hash(__dirname + '/files/castle1.png');
  const h2 = await imghash.hash(__dirname + '/files/absolut1');
  const dist = leven(h1, h2);
  expect(dist).toBeGreaterThan(12);
});

it('should create close hashes similar images', async () => {
  const h1 = await imghash.hash(__dirname + '/files/absolut2');
  const h2 = await imghash.hash(__dirname + '/files/absolut1');
  const dist = leven(h1, h2);
  expect(dist).not.toBe(0);
  expect(dist).toBeLessThan(14);
});

it('should support binary output', async () => {
  const h1 = imghash.hash(__dirname + '/files/absolut1', null, 'hex');
  const h2 = imghash.hash(__dirname + '/files/absolut1', null, 'binary');
  expect(h1).not.toBe(h2);
});

/**
 * pngcheck shows this image to have 4-bit palette color type which png-js doesn't handle well:
 * pngcheck test/files/Arius.png
 * OK: test/files/Arius.png (150x200, 4-bit palette, non-interlaced, 14.7%).
 *
 * see: https://github.com/commonsmachinery/blockhash-js/issues/7
 */
it('should hash palette based pngs correctly', async () => {
  const h1 = await imghash.hash(__dirname + '/files/Arius.png', 16, 'hex');
  const h2 = '0ff91ff10ff1008300018fd986d79ddf9e058fc30fc30fc3dfc3c3c30b831783';
  expect(h1).toBe(h2);
});

it('should support validate output format', () => {
  expect(() => {
    imghash.hash(__dirname + '/files/absolut1', null, 'foo');
  }).toThrow();
});

it('should support variable bits length', async () => {
  const h1 = await imghash.hash(__dirname + '/files/absolut1', 8);
  const h2 = await imghash.hash(__dirname + '/files/absolut1', 16);
  expect(h1.length * 4).toBe(h2.length);
});

it('should validate bit lengths', function() {
  expect(() => {
    imghash.hash(__dirname + '/files/absolut1', 10);
  }).toThrow();
});

it('should expose hexToBinary', () => {
  expect(imghash.hexToBinary('83C3D381C38985A5')).toBe('1000001111000011110100111000000111000011100010011000010110100101');
});

it('should expose binaryToHex', () => {
  expect(imghash.binaryToHex('1000001111000011110100111000000111000011100010011000010110100101')).toBe('83c3d381c38985a5');
});

it('should accept Buffer input', async () => {
  const buffer = fs.readFileSync(__dirname + '/files/absolut1');
  const hash = await imghash.hash(buffer);
  expect(hash).not.toBeNull();
});