feat: add font conversion dependencies and test fixtures

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

test/converters/font.test.js

@@ -0,0 +1,32 @@
+import { describe, it, expect } from 'vitest';
+import fs from 'node:fs/promises';
+import path from 'node:path';
+import opentype from 'opentype.js';
+import * as fontkit from 'fontkit';
+
+async function parseWithOpentype(fixtureName) {
+  const buf = await fs.readFile(path.join(import.meta.dirname, '..', 'fixtures', fixtureName));
+  const ab = buf.buffer.slice(buf.byteOffset, buf.byteOffset + buf.byteLength);
+  return opentype.parse(ab);
+}
+
+describe('font fixtures', () => {
+  it('sample.otf parses as a CFF-flavored OpenType font', async () => {
+    const font = await parseWithOpentype('sample.otf');
+    expect(font.outlinesFormat).toBe('cff');
+    expect(font.glyphs.length).toBe(1568);
+  });
+
+  it('sample.ttf parses as a TrueType font with the same glyph count as sample.otf', async () => {
+    const font = await parseWithOpentype('sample.ttf');
+    expect(font.outlinesFormat).toBe('truetype');
+    expect(font.glyphs.length).toBe(1568);
+  });
+
+  it('sample.dfont is a valid dfont container with one embedded sfnt font', async () => {
+    const buffer = await fs.readFile(path.join(import.meta.dirname, '..', 'fixtures', 'sample.dfont'));
+    const dfont = fontkit.create(buffer);
+    const sfntType = dfont.header.map.typeList.types.find((t) => t.name === 'sfnt');
+    expect(sfntType.refList).toHaveLength(1);
+  });
+});

test/fixtures/FONT_ATTRIBUTION.md

@@ -0,0 +1,15 @@
+# Font fixture attribution
+
+`sample.otf` and `sample.ttf` are the Regular weight of
+[Source Code Pro](https://github.com/adobe-fonts/source-code-pro) by Adobe,
+licensed under the SIL Open Font License 1.1 (see that repo's
+`LICENSE.md`). Both are the same font family deliberately, so tests can
+assert glyph-count fidelity (1568 glyphs) across otf/ttf/woff conversions
+of "the same font" rather than comparing unrelated files.
+
+`sample.dfont` is `Tests/ttx/data/TestDFONT.dfont` from
+[fonttools/fonttools](https://github.com/fonttools/fonttools), MIT
+licensed. It is a small (3.5KB) fixture containing one real embedded
+`sfnt` TrueType resource (7 glyphs) — used to exercise this project's
+dfont-container extraction code without needing a large real-world
+font suitcase.