### Question:
FusionIndexPopulator extends FusionIndexBase<IndexPopulator> implements IndexPopulator { @Override public void verifyDeferredConstraints( NodePropertyAccessor nodePropertyAccessor ) throws IndexEntryConflictException { for ( IndexSlot slot : IndexSlot.values() ) { instanceSelector.select( slot ).verifyDeferredConstraints( nodePropertyAccessor ); } } FusionIndexPopulator( SlotSelector slotSelector, InstanceSelector<IndexPopulator> instanceSelector, long indexId, IndexDropAction dropAction,
            boolean archiveFailedIndex ); @Override void create(); @Override void drop(); @Override void add( Collection<? extends IndexEntryUpdate<?>> updates ); @Override void verifyDeferredConstraints( NodePropertyAccessor nodePropertyAccessor ); @Override IndexUpdater newPopulatingUpdater( NodePropertyAccessor accessor ); @Override void close( boolean populationCompletedSuccessfully ); @Override void markAsFailed( String failure ); @Override void includeSample( IndexEntryUpdate<?> update ); @Override IndexSample sampleResult(); @Override Map<String,Value> indexConfig();  }### Answer:
@Test public void verifyDeferredConstraintsMustThrowIfAnyThrow() throws Exception { for ( IndexPopulator alivePopulator : alivePopulators ) { IndexEntryConflictException failure = mock( IndexEntryConflictException.class ); doThrow( failure ).when( alivePopulator ).verifyDeferredConstraints( any() ); verifyCallFail( failure, () -> { fusionIndexPopulator.verifyDeferredConstraints( null ); return null; } ); doAnswer( invocation -> null ).when( alivePopulator ).verifyDeferredConstraints( any() ); } }