@Test
public void testGetPrefixes() throws Exception {

    NamespaceRegistry delegate = mock(NamespaceRegistry.class);
    NamespaceRegistryFacade facade = getFacade(delegate);
    final String[] prefixes = new String[]{"jcr", "nt", "oak"};
    when(delegate.getPrefixes()).thenReturn(prefixes);
    assertSame("should be same", prefixes, facade.getPrefixes());
}