@Test public void toDigit() {

    assertThat(CharBuffer.toDigit('0'), is(0));
    assertThat(CharBuffer.toDigit('1'), is(1));
    assertThat(CharBuffer.toDigit('2'), is(2));
    assertThat(CharBuffer.toDigit('3'), is(3));
    assertThat(CharBuffer.toDigit('4'), is(4));
    assertThat(CharBuffer.toDigit('5'), is(5));
    assertThat(CharBuffer.toDigit('6'), is(6));
    assertThat(CharBuffer.toDigit('7'), is(7));
    assertThat(CharBuffer.toDigit('8'), is(8));
    assertThat(CharBuffer.toDigit('9'), is(9));
}