Support APNGs in Sticker Creator

ts/test/util/getAnimatedPngDataIfExists_test.ts

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+import * as fs from 'fs';
+import * as path from 'path';
+import { assert } from 'chai';
+
+import { getAnimatedPngDataIfExists } from '../../util/getAnimatedPngDataIfExists';
+
+describe('getAnimatedPngDataIfExists', () => {
+  const fixture = (filename: string): Promise<Buffer> => {
+    const fixturePath = path.join(
+      __dirname,
+      '..',
+      '..',
+      '..',
+      'fixtures',
+      filename
+    );
+    return fs.promises.readFile(fixturePath);
+  };
+
+  it('returns null for empty buffers', () => {
+    assert.isNull(getAnimatedPngDataIfExists(Buffer.alloc(0)));
+  });
+
+  it('returns null for non-PNG files', async () => {
+    await Promise.all(
+      [
+        'kitten-1-64-64.jpg',
+        '512x515-thumbs-up-lincoln.webp',
+        'giphy-GVNvOUpeYmI7e.gif',
+        'pixabay-Soap-Bubble-7141.mp4',
+        'lorem-ipsum.txt',
+      ].map(async filename => {
+        assert.isNull(getAnimatedPngDataIfExists(await fixture(filename)));
+      })
+    );
+  });
+
+  it('returns null for non-animated PNG files', async () => {
+    assert.isNull(
+      getAnimatedPngDataIfExists(await fixture('20x200-yellow.png'))
+    );
+  });
+
+  it('returns data for animated PNG files', async () => {
+    assert.deepEqual(
+      getAnimatedPngDataIfExists(
+        await fixture('Animated_PNG_example_bouncing_beach_ball.png')
+      ),
+      { numPlays: Infinity }
+    );
+
+    assert.deepEqual(
+      getAnimatedPngDataIfExists(await fixture('apng_with_2_plays.png')),
+      { numPlays: 2 }
+    );
+  });
+});

ts/test/util/sniffImageMimeType_test.ts

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+import * as fs from 'fs';
+import * as path from 'path';
+import { assert } from 'chai';
+import {
+  IMAGE_BMP,
+  IMAGE_GIF,
+  IMAGE_ICO,
+  IMAGE_JPEG,
+  IMAGE_PNG,
+  IMAGE_WEBP,
+} from '../../types/MIME';
+
+import { sniffImageMimeType } from '../../util/sniffImageMimeType';
+
+describe('sniffImageMimeType', () => {
+  const fixture = (filename: string): Promise<Buffer> => {
+    const fixturePath = path.join(
+      __dirname,
+      '..',
+      '..',
+      '..',
+      'fixtures',
+      filename
+    );
+    return fs.promises.readFile(fixturePath);
+  };
+
+  it('returns undefined for empty buffers', () => {
+    assert.isUndefined(sniffImageMimeType(new Uint8Array()));
+  });
+
+  it('returns undefined for non-image files', async () => {
+    await Promise.all(
+      ['pixabay-Soap-Bubble-7141.mp4', 'lorem-ipsum.txt'].map(
+        async filename => {
+          assert.isUndefined(sniffImageMimeType(await fixture(filename)));
+        }
+      )
+    );
+  });
+
+  it('sniffs ICO files', async () => {
+    assert.strictEqual(
+      sniffImageMimeType(await fixture('kitten-1-64-64.ico')),
+      IMAGE_ICO
+    );
+  });
+
+  it('sniffs BMP files', async () => {
+    assert.strictEqual(sniffImageMimeType(await fixture('2x2.bmp')), IMAGE_BMP);
+  });
+
+  it('sniffs GIF files', async () => {
+    assert.strictEqual(
+      sniffImageMimeType(await fixture('giphy-GVNvOUpeYmI7e.gif')),
+      IMAGE_GIF
+    );
+  });
+
+  it('sniffs WEBP files', async () => {
+    assert.strictEqual(
+      sniffImageMimeType(await fixture('512x515-thumbs-up-lincoln.webp')),
+      IMAGE_WEBP
+    );
+  });
+
+  it('sniffs PNG files', async () => {
+    await Promise.all(
+      [
+        'freepngs-2cd43b_bed7d1327e88454487397574d87b64dc_mv2.png',
+        'Animated_PNG_example_bouncing_beach_ball.png',
+      ].map(async filename => {
+        assert.strictEqual(
+          sniffImageMimeType(await fixture(filename)),
+          IMAGE_PNG
+        );
+      })
+    );
+  });
+
+  it('sniffs JPEG files', async () => {
+    assert.strictEqual(
+      sniffImageMimeType(await fixture('kitten-1-64-64.jpg')),
+      IMAGE_JPEG
+    );
+  });
+
+  it('handles ArrayBuffers', async () => {
+    const arrayBuffer = (await fixture('kitten-1-64-64.jpg')).buffer;
+    assert.strictEqual(sniffImageMimeType(arrayBuffer), IMAGE_JPEG);
+  });
+});