### Question:
FusionIndexUpdater extends FusionIndexBase<IndexUpdater> implements IndexUpdater { @Override public void close() throws IndexEntryConflictException { AtomicReference<IndexEntryConflictException> chainedExceptions = new AtomicReference<>(); instanceSelector.close( indexUpdater -> { try { indexUpdater.close(); } catch ( IndexEntryConflictException e ) { if ( !chainedExceptions.compareAndSet( null, e ) ) { chainedExceptions.get().addSuppressed( e ); } } } ); if ( chainedExceptions.get() != null ) { throw chainedExceptions.get(); } } FusionIndexUpdater( SlotSelector slotSelector, LazyInstanceSelector<IndexUpdater> instanceSelector ); @Override void process( IndexEntryUpdate<?> update ); @Override void close();  }### Answer:
@Test public void closeMustCloseAll() throws Exception { fusionIndexUpdater.close(); for ( IndexUpdater updater : aliveUpdaters ) { verify( updater, times( 1 ) ).close(); } }