@Test
public void nitrogen_neutral() {

    assertThat(MDLValence.implicitValence(7, 0, 0), is(3));
    assertThat(MDLValence.implicitValence(7, 0, 1), is(3));
    assertThat(MDLValence.implicitValence(7, 0, 2), is(3));
    assertThat(MDLValence.implicitValence(7, 0, 3), is(3));
    assertThat(MDLValence.implicitValence(7, 0, 4), is(5));
    assertThat(MDLValence.implicitValence(7, 0, 5), is(5));
    assertThat(MDLValence.implicitValence(7, 0, 6), is(6));
}