import { assert, describe, it } from "@effect/vitest"; import { encodePngIco, readPngDimensions } from "./icon-export.ts"; const pngHeader = (width: number, height: number) => {  const contents = Buffer.alloc(24);  Buffer.from([0x89, 0x50, 0x4e, 0x47, 0x0d, 0x0a, 0x1a, 0x0a]).copy(contents);  contents.write("IHDR", 12, "ascii");  contents.writeUInt32BE(width, 16);  contents.writeUInt32BE(height, 20);  return contents;}; describe("icon export", () => {  it("reads dimensions from a PNG IHDR chunk", () => {    assert.deepEqual(readPngDimensions(pngHeader(1024, 512)), { width: 1024, height: 512 });  });   it("encodes PNG renditions into an ICO directory", () => {    const small = pngHeader(16, 16);    const large = pngHeader(256, 256);    const ico = encodePngIco([      { size: 16, contents: small },      { size: 256, contents: large },    ]);     assert.equal(ico.readUInt16LE(2), 1);    assert.equal(ico.readUInt16LE(4), 2);    assert.equal(ico.readUInt8(6), 16);    assert.equal(ico.readUInt8(22), 0);    assert.equal(ico.readUInt32LE(18), 38);    assert.equal(ico.readUInt32LE(34), 38 + small.length);    assert.deepEqual(ico.subarray(38, 38 + small.length), small);    assert.deepEqual(ico.subarray(38 + small.length), large);  });   it("rejects duplicate ICO rendition sizes", () => {    assert.throws(      () =>        encodePngIco([          { size: 32, contents: pngHeader(32, 32) },          { size: 32, contents: pngHeader(32, 32) },        ]),      /provided more than once/,    );  });});