private static byte[] keyAfter(byte[] key) {
    return Arrays.copyOf(key, key.length + 1);
  }
Verifies scenario for finding a split point.
@param splitPointAfter    Stripe to expect the split point at/after.
@param shouldSplitStripe  If true, the split point is expected in the middle of the above
                          stripe; if false, should be at the end.
@param splitRatioToVerify Maximum split imbalance ratio.
@param sizes              Stripe sizes.
hbase-server/src/test/java/org/apache/hadoop/hbase/regionserver/TestStripeStoreFileManager.java