question: public void testCase5 ( ) { byte aBytes [ ] = { 10 , 20 , 30 , 40 , 50 , 60 , 70 , 10 , 20 , 30 } ; byte bBytes [ ] = { 1 , 2 , 3 , 4 , 5 , 6 , 7 , 1 , 2 , 3 } ; int aSign = - 1 ; int bSign = - 1 ; byte rBytes [ ] = { - 10 , - 19 , - 28 , - 37 , - 46 , - 55 , - 64 , - 10 , - 19 , - 27 } ; BigInteger aNumber = new BigInteger ( aSign , aBytes ) ; BigInteger bNumber = new BigInteger ( bSign , bBytes ) ; BigInteger result = aNumber . subtract ( bNumber ) ; byte resBytes [ ] = new byte [ rBytes . length ] ; resBytes = result . toByteArray ( ) ; for ( int i = 0 ; i < resBytes . length ; i ++ ) { assertTrue ( resBytes [ i ] == rBytes [ i ] ) ; } assertEquals ( - 1 , result . signum ( ) ) ; }
target:  Subtract two negative numbers of the same length. The first is greater in absolute value.