@Override
    public void beforeUpdate(EntryEvent event) throws CacheWriterException {
      assertTrue(event.getOperation().isUpdate());
      assertTrue(event.getRegion().containsKey(key));
      assertTrue(event.getRegion().containsValueForKey(key));
      assertNotNull(event.getRegion().getEntry(key));
      assertNotSame(value, event.getRegion().get(key));
      validationSuccessful = true;
    }
This method validates create operations. It verfies that entries are created and if entry
already exists, it throws EntryExistsException.
geode-core/src/integrationTest/java/org/apache/geode/internal/cache/PartitionedRegionSingleNodeOperationsJUnitTest.java