### Question:
ColumnRegistryInitializer { void initialize() { final List<Item> allColumns = columnStorage.getAllColumns(); for (Item next : allColumns) { registry.register(next); } registry.register(new ColumnBuilder().build()); } ColumnRegistryInitializer(ColumnRegistry registry, ColumnStorage storage);   }### Answer:
@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); }