frontend: add unit tests for base58.ts

Author: ffreddow

frontend/src/base58.test.ts

@@ -0,0 +1,67 @@
+import { describe, it, expect } from 'vitest';
+import { encodeBase58Flickr } from './base58';
+
+// Alphabet used by encodeBase58Flickr for reference:
+// '123456789abcdefghijkmnopqrstuvwxyzABCDEFGHJKLMNPQRSTUVWXYZ'
+
+describe('encodeBase58Flickr', () => {
+  it('encodes empty input as "1"', () => {
+    const input = new Uint8Array([]);
+    expect(encodeBase58Flickr(input)).toBe('1');
+  });
+
+  it('encodes a single zero byte as "1"', () => {
+    const input = new Uint8Array([0x00]);
+    expect(encodeBase58Flickr(input)).toBe('1');
+  });
+
+  it('encodes multiple zero bytes as a single "1" (value is zero)', () => {
+    const input = new Uint8Array([0x00, 0x00]);
+    // value remains 0n -> early return
+    expect(encodeBase58Flickr(input)).toBe('1');
+  });
+
+  it('preserves leading zeroes as leading "1" characters', () => {
+    const input = new Uint8Array([0x00, 0xff]);
+    // 0xff -> base58 Flickr is '5p' and one leading zero -> '1' prefix
+    expect(encodeBase58Flickr(input)).toBe('15p');
+  });
+
+  it('encodes a non-zero single byte correctly', () => {
+    const input = new Uint8Array([0xff]);
+    // 255 -> 58*4=232 remainder 23 -> indices [4,23] => '5p'
+    expect(encodeBase58Flickr(input)).toBe('5p');
+  });
+
+  it('encodes multiple bytes without leading zeros', () => {
+    const input = new Uint8Array([0x01, 0x02]); // 258 decimal
+    // 258 -> 58*4=232 remainder 26 -> indices [4,26] => '5s'
+    expect(encodeBase58Flickr(input)).toBe('5s');
+  });
+
+  it('handles multiple leading zeroes (prefix with multiple 1s)', () => {
+    const input = new Uint8Array([0x00, 0x00, 0x01]);
+    // value=1 -> '2', with two leading zeros -> '112'
+    expect(encodeBase58Flickr(input)).toBe('112');
+  });
+
+  it('encodes 58 correctly (two digits)', () => {
+    const input = new Uint8Array([0x3a]); // 58 decimal
+    // 58 -> digits [0,1] => '21' with Flickr alphabet
+    expect(encodeBase58Flickr(input)).toBe('21');
+  });
+
+  it('encodes 256 correctly and with leading zeros', () => {
+    const noLeading = new Uint8Array([0x01, 0x00]); // 256 decimal -> '5q'
+    expect(encodeBase58Flickr(noLeading)).toBe('5q');
+
+    const withLeading = new Uint8Array([0x00, 0x00, 0x01, 0x00]); // two leading zeros + 256 -> '115q'
+    expect(encodeBase58Flickr(withLeading)).toBe('115q');
+  });
+
+  it('encodes with multiple leading zeros before 0xff (255)', () => {
+    const input = new Uint8Array([0x00, 0x00, 0xff]);
+    // base value 255 => '5p', two leading zeros -> prefix '11'
+    expect(encodeBase58Flickr(input)).toBe('115p');
+  });
+});