question: public void testLongConversionAndOrdering ( ) throws Exception { BytesRef previous = null ; BytesRef current = new BytesRef ( new byte [ Long . BYTES ] ) ; for ( long value = - 100000L ; value < 100000L ; value ++ ) { NumericUtils . longToSortableBytes ( value , current . bytes , current . offset ) ; if ( previous == null ) { previous = new BytesRef ( new byte [ Long . BYTES ] ) ; } else { assertTrue ( "current bigger than previous: " , previous . compareTo ( current ) < 0 ) ; } assertEquals ( "forward and back conversion should generate same long" , value , NumericUtils . sortableBytesToLong ( current . bytes , current . offset ) ) ; System . arraycopy ( current . bytes , current . offset , previous . bytes , previous . offset , current . length ) ; } }
target:  generate a series of encoded longs, each numerical one bigger than the one before. check for correct ordering of the encoded bytes and that values round-trip.