@Test
public void testIsAccepted() throws Exception {

    NodeFilter f1 = new OrFilter(new TrueFilter(), new TrueFilter());
    assertThat(f1.isAccepted(new Node("x")), is(true));
    NodeFilter f2 = new OrFilter(new TrueFilter(), new NotFilter(new TrueFilter()));
    assertThat(f2.isAccepted(new Node("x")), is(true));
    NodeFilter f3 = new OrFilter(new NotFilter(new TrueFilter()), new NotFilter(new TrueFilter()));
    assertThat(f3.isAccepted(new Node("x")), is(false));
}