@Test
public void hasAtleastOneLetter_shouldReturnTrue_whenStringHasAtleastOneLetter() throws
    Exception {

  assertEquals(true, validateTor.hasAtleastOneLetter("abcde1"));
  assertEquals(true, validateTor.hasAtleastOneLetter("a1b2c3"));
  assertEquals(true, validateTor.hasAtleastOneLetter("123abc"));
  assertEquals(true, validateTor.hasAtleastOneLetter("abcdef"));
  assertEquals(true, validateTor.hasAtleastOneLetter("ABC"));
  assertEquals(true, validateTor.hasAtleastOneLetter("AB123"));
  assertEquals(true, validateTor.hasAtleastOneLetter("aBcD123#"));
}