    @Test
    public void testAsByte() throws Exception {

        Document document = XpathUtils.documentFrom(DOCUMENT);
        assertEquals(new Byte((byte) 123), XpathUtils.asByte("Foo/PositiveByte", document));
        assertEquals(new Byte((byte) -99), XpathUtils.asByte("Foo/NegativeByte", document));
        assertEquals(null, XpathUtils.asByte("Foo/Empty", document));
    }