test: add long/short zeros and max char base58 tests

Author: ChALkeR

base58.js

@@ -121,7 +121,6 @@ function toBase58core(arr, alphabet, codes) {
   return ZERO.repeat(zeros) + out
 }
 
-// TODO: test on 'z'.repeat(from 1 to smth)
 function fromBase58core(str, alphabet, codes, format = 'uint8') {
   if (typeof str !== 'string') throw new TypeError('Input is not a string')
   const length = str.length

tests/base58.test.js

@@ -3,6 +3,16 @@ import { randomValues } from '@exodus/crypto/randomBytes'
 import { test } from 'node:test'
 import bs58 from 'bs58'
 
+test('zeros', (t) => {
+  for (let size = 0; size <= 1024; size++) {
+    const zeros = new Uint8Array(size)
+    const expected = '1'.repeat(size)
+    t.assert.strictEqual(toBase58(zeros), expected, `[0] x${size} toBase58`)
+    t.assert.strictEqual(bs58.encode(zeros), expected, `[0] x${size} bs58.encode`) // matches bs58
+    t.assert.deepStrictEqual(fromBase58(expected), zeros, `[0] x${size} fromBase58`)
+  }
+})
+
 test('toBase58 matches bs58, static data', (t) => {
   for (let size = 0; size < 180; size++) {
     const zeros = new Uint8Array(size)
@@ -16,6 +26,16 @@ test('toBase58 matches bs58, static data', (t) => {
   }
 })
 
+test('toBase58 matches bs58, maximum char repeated', (t) => {
+  const maxChar = 'z'
+  for (let size = 0; size < 300; size++) {
+    const encoded = maxChar.repeat(size)
+    const decoded = fromBase58(encoded)
+    t.assert.strictEqual(toBase58(decoded), encoded, `${maxChar} x${size} toBase58`)
+    t.assert.strictEqual(bs58.encode(decoded), encoded, `${maxChar} x${size}`) // matches bs58
+  }
+})
+
 test('sizes roundtrip, static data', (t) => {
   for (let size = 0; size < 260; size++) {
     const zeros = new Uint8Array(size)