@Test
public void testGetURI() throws Exception {

    NamespaceRegistry delegate = mock(NamespaceRegistry.class);
    NamespaceRegistryFacade facade = getFacade(delegate);
    final String prefix = NamespaceRegistry.PREFIX_JCR;
    final String uri = NamespaceRegistry.NAMESPACE_JCR;
    when(delegate.getURI(anyString())).thenReturn(null);
    when(delegate.getURI(prefix)).thenReturn(uri);
    assertNull("should be null", facade.getURI(""));
    assertSame("should be same", uri, facade.getURI(prefix));
}