@Test
public void testHexStringToByteArray() {

    assertThat(Numeric.hexStringToByteArray(""), is(new byte[]{}));
    assertThat(Numeric.hexStringToByteArray("0"), is(new byte[]{0}));
    assertThat(Numeric.hexStringToByteArray("1"), is(new byte[]{0x1}));
    assertThat(Numeric.hexStringToByteArray(HEX_RANGE_STRING),
            is(HEX_RANGE_ARRAY));
    assertThat(Numeric.hexStringToByteArray("0x123"),
            is(new byte[]{0x1, 0x23}));
}