@Test
public void testInitialize() {

    final ColumnStorage storage = mock(ColumnStorage.class);
    final List<Item> columnList = new ArrayList<>();
    columnList.add(new ColumnBuilder().name("col_1").build());
    columnList.add(new ColumnBuilder().name("col_2").build());
    when(storage.getAllColumns()).thenReturn(columnList);
    final ColumnRegistry registry = new ColumnRegistry();
    final ColumnRegistryInitializer initializer = new ColumnRegistryInitializer(registry, storage);
    initializer.initialize();
    Item item = registry.getColumn("col_1");
    assertNotNull(item);
    item = registry.getColumn("col_2");
    assertNotNull(item);
    item = registry.getColumn("Implicit");
    assertNotNull(item);
    verify(storage, times(1)).getAllColumns();
    verifyNoMoreInteractions(storage);
}