code: @Test public void testGetAlphanumericCode(){
    for (int i=0; i < 10; ++i) {
      assertEquals(i,Encoder.getAlphanumericCode('0' + i));
    }
    for (int i=10; i < 36; ++i) {
      assertEquals(i,Encoder.getAlphanumericCode('A' + i - 10));
    }
    assertEquals(36,Encoder.getAlphanumericCode(' '));
    assertEquals(37,Encoder.getAlphanumericCode('$'));
    assertEquals(38,Encoder.getAlphanumericCode('%'));
    assertEquals(39,Encoder.getAlphanumericCode('*'));
    assertEquals(40,Encoder.getAlphanumericCode('+'));
    assertEquals(41,Encoder.getAlphanumericCode('-'));
    assertEquals(42,Encoder.getAlphanumericCode('.'));
    assertEquals(43,Encoder.getAlphanumericCode('/'));
    assertEquals(44,Encoder.getAlphanumericCode(':'));
    assertEquals(-1,Encoder.getAlphanumericCode('a'));
    assertEquals(-1,Encoder.getAlphanumericCode('#'));
    assertEquals(-1,Encoder.getAlphanumericCode('\0'));
  }
  