SnowLuma/packages/core/tests/hex.test.ts

import { describe, it, expect } from 'vitest';
import { toHex, fromHex, hexPreview } from '@snowluma/common/hex';

describe('toHex', () => {
    it('converts empty buffer', () => {
        expect(toHex(new Uint8Array(0))).toBe('');
    });

    it('converts single byte', () => {
        expect(toHex(new Uint8Array([0xff]))).toBe('ff');
        expect(toHex(new Uint8Array([0x00]))).toBe('00');
        expect(toHex(new Uint8Array([0x0a]))).toBe('0a');
    });

    it('converts multiple bytes', () => {
        expect(toHex(new Uint8Array([0xde, 0xad, 0xbe, 0xef]))).toBe('deadbeef');
    });

    it('works with Buffer', () => {
        expect(toHex(Buffer.from([0x01, 0x23, 0x45]))).toBe('012345');
    });
});

describe('fromHex', () => {
    it('converts empty string', () => {
        expect(fromHex('')).toEqual(Buffer.alloc(0));
    });

    it('converts hex string', () => {
        const buf = fromHex('deadbeef');
        expect(buf).toEqual(Buffer.from([0xde, 0xad, 0xbe, 0xef]));
    });

    it('handles uppercase', () => {
        const buf = fromHex('DEADBEEF');
        expect(buf).toEqual(Buffer.from([0xde, 0xad, 0xbe, 0xef]));
    });

    it('throws on odd-length string', () => {
        expect(() => fromHex('abc')).toThrow('Invalid hex string length');
    });

    it('roundtrips with toHex', () => {
        const original = Buffer.from([0x00, 0x7f, 0x80, 0xff]);
        expect(fromHex(toHex(original))).toEqual(original);
    });
});

describe('hexPreview', () => {
    it('shows full hex for small data', () => {
        const data = new Uint8Array([0xab, 0xcd]);
        expect(hexPreview(data)).toBe('abcd');
    });

    it('truncates with ellipsis', () => {
        const data = new Uint8Array(128).fill(0xaa);
        const preview = hexPreview(data, 4);
        expect(preview).toBe('aaaaaaaa...');
    });

    it('no ellipsis when exactly at limit', () => {
        const data = new Uint8Array(4).fill(0xbb);
        expect(hexPreview(data, 4)).toBe('bbbbbbbb');
    });
});