### Question:
StringUtils { public static String ConvertArabicToLetters(int num) { String letters = ""; while (num > 0) { num--; letters = Character.toString((char) (65 + (num % 26))) + letters; num = num / 26; } return letters.toString(); }  static String ConvertArabicToLetters(int num); static String stripQuotes(final String string);  }### Answer:
@Test public void testConvertNumbersLen2() { String str = StringUtils.ConvertArabicToLetters(27); assertTrue(str.equals("AA")); }
@Test public void testConvertNumbersLen1() { String str = StringUtils.ConvertArabicToLetters(3); assertTrue(str.equals("C")); }