cinny/src/app/utils/imageCompression.test.ts

import { test } from 'node:test';
import assert from 'node:assert/strict';
import {
  formatFileSize,
  hasTransparency,
  isAnimatedWebp,
  isCompressible,
} from './imageCompression';

test('formatFileSize formats bytes below 1KB as B', () => {
  assert.equal(formatFileSize(0), '0 B');
  assert.equal(formatFileSize(1), '1 B');
  assert.equal(formatFileSize(512), '512 B');
  assert.equal(formatFileSize(1023), '1023 B');
});

test('formatFileSize formats values in the KB range', () => {
  assert.equal(formatFileSize(1024), '1.0 KB');
  assert.equal(formatFileSize(1536), '1.5 KB');
  // 1024 * 1024 - 1 is still under the MB boundary
  assert.equal(formatFileSize(1024 * 1024 - 1), '1024.0 KB');
});

test('formatFileSize formats values in the MB range', () => {
  assert.equal(formatFileSize(1024 * 1024), '1.0 MB');
  assert.equal(formatFileSize(1024 * 1024 * 1.5), '1.5 MB');
  assert.equal(formatFileSize(1024 * 1024 * 10), '10.0 MB');
});

test('isCompressible accepts raster image types', () => {
  assert.equal(isCompressible({ type: 'image/png' } as Blob), true);
  assert.equal(isCompressible({ type: 'image/jpeg' } as Blob), true);
  assert.equal(isCompressible({ type: 'image/webp' } as Blob), true);
});

test('isCompressible rejects svg, empty type, and non-images', () => {
  assert.equal(isCompressible({ type: 'image/svg+xml' } as Blob), false);
  // [Gitea #331] usually animated; a canvas keeps one frame
  assert.equal(isCompressible({ type: 'image/gif' } as Blob), false);
  assert.equal(isCompressible({ type: 'image/apng' } as Blob), false);
  assert.equal(isCompressible({ type: '' } as Blob), false);
  assert.equal(isCompressible({ type: 'application/pdf' } as Blob), false);
  assert.equal(isCompressible({ type: 'text/plain' } as Blob), false);
  assert.equal(isCompressible({ type: 'video/mp4' } as Blob), false);
});

const webpHeader = (chunk: string, flags = 0) => {
  const b = new Uint8Array(32);
  const put = (at: number, str: string) => b.set(new TextEncoder().encode(str), at);
  put(0, 'RIFF');
  put(8, 'WEBP');
  put(12, chunk);
  b[20] = flags;
  return b;
};

test('isAnimatedWebp: VP8X with the animation flag (#331)', () => {
  assert.equal(isAnimatedWebp(webpHeader('VP8X', 0x02)), true);
  assert.equal(isAnimatedWebp(webpHeader('VP8X', 0x10)), false, 'alpha flag only');
  assert.equal(isAnimatedWebp(webpHeader('VP8 ')), false, 'simple lossy');
  assert.equal(isAnimatedWebp(new Uint8Array(8)), false);
});

test('hasTransparency (#331)', () => {
  assert.equal(hasTransparency(new Uint8ClampedArray([1, 2, 3, 255, 4, 5, 6, 255])), false);
  assert.equal(hasTransparency(new Uint8ClampedArray([1, 2, 3, 255, 0, 0, 0, 0])), true);
});