fix big input threshold computation

lib/server.js

@@ -1410,7 +1410,7 @@ WalletService.prototype._selectTxInputs2 = function(txp, utxosToExclude, cb) {
       return false;
     }
 
-    var bigInputThreshold = txpAmount * Defaults.UTXO_SELECTION_MAX_SINGLE_UTXO_FACTOR;
+    var bigInputThreshold = txpAmount * Defaults.UTXO_SELECTION_MAX_SINGLE_UTXO_FACTOR + (baseTxpFee + feePerInput);
     log.debug('Big input threshold ' + formatAmount(bigInputThreshold));
 
     var partitions = _.partition(utxos, function(utxo) {
@@ -1562,8 +1562,14 @@ WalletService.prototype._selectTxInputs2 = function(txp, utxosToExclude, cb) {
     if (txp.getEstimatedSize() / 1000 > Defaults.MAX_TX_SIZE_IN_KB)
       return cb(Errors.TX_MAX_SIZE_EXCEEDED);
 
-    var bitcoreError = self._checkTxAndEstimateFee(txp);
-    return cb(bitcoreError);
+    var err = self._checkTxAndEstimateFee(txp);
+    if (!err) {
+      log.debug('Successfully built transaction. Total fees: ', formatAmount(txp.fee));
+    } else {
+      log.warn('Error building transaction', err);
+    }
+
+    return cb(err);
   });
 };
 

test/integration/server.js

@@ -5760,7 +5760,6 @@ describe('Wallet service', function() {
         });
       });
     });
-
     it('should select smaller utxos if within fee constraints', function(done) {
       helpers.stubUtxos(server, wallet, [1, '800bit', '800bit', '800bit'], function() {
         var txOpts = {
@@ -5799,6 +5798,30 @@ describe('Wallet service', function() {
         });
       });
     });
+    it('should account for fee when selecting smallest big utxo', function(done) {
+      // log.level = 'debug';
+      var _old = Defaults.UTXO_SELECTION_MAX_SINGLE_UTXO_FACTOR;
+      Defaults.UTXO_SELECTION_MAX_SINGLE_UTXO_FACTOR = 2;
+      // The 605 bits input cannot be selected even if it is > 2 * tx amount
+      // because it cannot cover for fee on its own.
+      helpers.stubUtxos(server, wallet, [1, '605bit', '100bit', '100bit', '100bit'], function() {
+        var txOpts = {
+          outputs: [{
+            toAddress: '18PzpUFkFZE8zKWUPvfykkTxmB9oMR8qP7',
+            amount: 300e2,
+          }],
+          feePerKb: 1200e2,
+        };
+        server.createTx(txOpts, function(err, txp) {
+          should.not.exist(err);
+          should.exist(txp);
+          txp.inputs.length.should.equal(1);
+          txp.inputs[0].satoshis.should.equal(1e8);
+          Defaults.UTXO_SELECTION_MAX_SINGLE_UTXO_FACTOR = _old;
+          done();
+        });
+      });
+    });
     it('should select smallest big utxo if small utxos exceed maximum fee', function(done) {
       helpers.stubUtxos(server, wallet, [3, 1, 2].concat(_.times(20, function() {
         return '1000bit';
@@ -5958,7 +5981,6 @@ describe('Wallet service', function() {
         });
       });
     });
-
   });
 
 });