@Test
public void testGetDescriptorValue() {

    final Repository mockRepository = mock(Repository.class);
    final String key = "SOME_KEY";
    final Value value = new SimpleValueFactory().createValue("SOME_VALUE");
    when(mockRepository.getDescriptorValue(anyString())).thenReturn(null);
    when(mockRepository.getDescriptorValue(key)).thenReturn(value);
    final RepositoryFacade facade = getFacade(mockRepository);
    assertSame("should be same value",
            value, facade.getDescriptorValue(key));
    assertNull("should be null",
            facade.getDescriptorValues(""));
    final RepositoryFacade facadeNull = getFacade(null);
    assertNull("should be null for null",
            facadeNull.getDescriptorValue(key));
}