refactor fee correction on change below dust

lib/server.js

@@ -1389,13 +1389,11 @@ WalletService.prototype._selectTxInputs = function(txp, utxosToExclude, cb) {
 
       if (netTotal >= txpAmount) {
         var changeAmount = Math.round(total - txpAmount - fee);
-
         log.debug('Tx change: ', Utils.formatAmountInBtc(changeAmount));
 
-        if (changeAmount != 0 && Math.abs(changeAmount) <= Bitcore.Transaction.DUST_AMOUNT) {
-          log.debug('ABS(Change) (' + Utils.formatAmountInBtc(changeAmount) + ') below dust amount (' + Utils.formatAmountInBtc(Bitcore.Transaction.DUST_AMOUNT) + ')');
-          if (changeAmount > 0 && fee < changeAmount) return;
-          // Either increment or decrement fee to remove change
+        if (changeAmount > 0 && changeAmount <= Bitcore.Transaction.DUST_AMOUNT) {
+          log.debug('Change below dust amount (' + Utils.formatAmountInBtc(Bitcore.Transaction.DUST_AMOUNT) + ')');
+          // Remove dust change by incrementing fee
           fee += changeAmount;
         }
 

test/integration/server.js

@@ -3540,6 +3540,8 @@ describe('Wallet service', function() {
           server.createTx(txOpts, function(err, txp) {
             should.not.exist(err);
             (_.sum(txp.inputs, 'satoshis') - txp.outputs[0].amount - txp.fee).should.equal(0);
+            var changeOutput = txp.getBitcoreTx().getChangeOutput();
+            should.not.exist(changeOutput);
             done();
           });
         });