@Test
public void shouldHaveSameNamespaceUriPassedIntoConstructor() {

    assertThat(ns1.getNamespaceUri(), is(validUri1));
    assertThat(ns2.getNamespaceUri(), is(validUri2));
    assertThat(ns3.getNamespaceUri(), is(validUri1));
    assertThat(ns4.getNamespaceUri(), is(validUri2));
    assertThat(ns5.getNamespaceUri(), is(validUri3));
}