Feat/fix fee calculations

karma.conf.js

@@ -8,6 +8,11 @@ module.exports = (config) => {
       './index.js': ['webpack'],
       './test.spec.js': ['webpack'],
     },
+    client: {
+      mocha: {
+        timeout: 60000
+      }
+    },
     webpack: {
       resolve: {
         fallback: {

lib/transaction/transaction.js

@@ -102,6 +102,8 @@ Transaction.FEE_PER_KB = 1000;
 Transaction.CHANGE_OUTPUT_MAX_SIZE = 20 + 4 + 34 + 4;
 Transaction.MAXIMUM_EXTRA_SIZE = 4 + 9 + 9 + 4;
 
+Transaction.MINIMUM_FEE = 255;
+
 Transaction.TYPES = registeredTransactionTypes;
 
 Transaction.CURRENT_VERSION = CURRENT_VERSION;
@@ -832,6 +834,21 @@ Transaction.prototype.feePerKb = function (amount) {
   return this;
 };
 
+/**
+ * Manually set the minimum fee's for this transaction. Beware that this resets all the signatures
+ * for inputs (in further versions, SIGHASH_SINGLE or SIGHASH_NONE signatures will not
+ * be reset).
+ *
+ * @param {number} amount satoshis per KB to be sent
+ * @return {Transaction} this, for chaining
+ */
+Transaction.prototype.minimumFee = function (amount) {
+  $.checkArgument(_.isNumber(amount), 'amount must be a number');
+  this._minimumFee = amount;
+  this._updateChangeOutput();
+  return this;
+};
+
 /* Output management */
 
 /**
@@ -1046,7 +1063,7 @@ Transaction.prototype.getFee = function () {
 Transaction.prototype._estimateFee = function () {
   var estimatedSize = this._estimateSize();
   var available = this._getUnspentValue();
-  return Transaction._estimateFee(estimatedSize, available, this._feePerKb);
+  return Transaction._estimateFee(estimatedSize, available, this._feePerKb, this._minimumFee);
 };
 
 Transaction.prototype._getUnspentValue = function () {
@@ -1059,23 +1076,30 @@ Transaction.prototype._clearSignatures = function () {
   });
 };
 
-Transaction._estimateFee = function (size, amountAvailable, feePerKb) {
-  var fee = Math.ceil(size / 1000) * (feePerKb || Transaction.FEE_PER_KB);
-  if (amountAvailable > fee) {
-    size += Transaction.CHANGE_OUTPUT_MAX_SIZE;
+Transaction._estimateFee = function (size, amountAvailable, feePerKb, minimumFee) {
+  var feePerByte = (feePerKb || Transaction.FEE_PER_KB) / 1000;
+  var fee = size * feePerByte;
+  if(fee<(minimumFee || Transaction.MINIMUM_FEE)){
+    return (minimumFee || Transaction.MINIMUM_FEE)
+  }
+  if (amountAvailable > fee + minimumFee) {
+    fee += (minimumFee || Transaction.MINIMUM_FEE);
   }
-  return Math.ceil(size / 1000) * (feePerKb || Transaction.FEE_PER_KB);
+  return fee;
 };
 
 Transaction.prototype._estimateSize = function () {
-  var result = Transaction.MAXIMUM_EXTRA_SIZE;
-  _.each(this.inputs, function (input) {
-    result += input._estimateSize();
-  });
-  _.each(this.outputs, function (output) {
-    result += output.script.toBuffer().length + 9;
-  });
-  return result;
+  // string format HEX -> 2 symbols == 1 byte
+  var serializedSize = this.toString().length / 2;
+  if ( !this.isFullySigned() ) {
+    // every signed input contains some additional bytes
+    serializedSize += this.inputs.length * PublicKeyHashInput.SCRIPT_MAX_SIZE;
+  }
+  if ( this._missingChange() ) {
+    serializedSize += Transaction.CHANGE_OUTPUT_MAX_SIZE;
+  }
+
+  return serializedSize;
 };
 
 Transaction.prototype._removeOutput = function (index) {

test/data/tx_creation.json

@@ -182,6 +182,6 @@
     "sign",
     ["XJoAwsbx9EqCp7PTMAWbhQsjFHDuQEaEJwcNS96F3ZKuPM4y8ntu"],
     "serialize",
-    "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"
+    "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"
   ]
 ]

test/transaction/transaction.js

@@ -235,6 +235,113 @@ describe('Transaction', function () {
     );
   });
 
+
+  describe('transaction fee calculation test', function () {
+    var minimalFee = 255;
+
+    var minimalUTXO = {
+      "satoshis": 5460 + 255,
+      "script": Script.buildPublicKeyHashOut('yfGjFr9Cu8AZYYrdeiRRNtLktWcJetxKv4').toString(),
+      "txid": '88d78d6afaa06bbe5943152757305338eba27cc1f3e84acb1a31ab17f26c038d',
+      outputIndex: 0,
+      address: "yfGjFr9Cu8AZYYrdeiRRNtLktWcJetxKv4"
+    }
+
+    var simpleUTXO = {
+      ...minimalUTXO,
+      "satoshis": 1000000000,
+    }
+
+    var privateKey = PrivateKey.fromWIF(
+      'cTtLHt4mv6zuJytSnM7Vd6NLxyNauYLMxD818sBC8PJ1UPiVTRSs'
+    )
+
+    it('should return correct minimal fee amount with 1 input and 1 output', () => {
+      var tx = new Transaction()
+        .from(minimalUTXO)
+        .to('yeB49jSYYp3786GQr7eKFwLNdEqonBf6hm', 5460)
+        .change('yeB49jSYYp3786GQr7eKFwLNdEqonBf6hm')
+
+      tx.getFee().should.equal(minimalFee);
+
+      tx.sign(privateKey);
+
+      tx.isFullySigned().should.equal(true);
+
+      tx.getFee().should.equal(minimalFee);
+
+      should.equal(tx.getChangeOutput(), null);
+    });
+
+    it('should return correct minimal fee amount with 30 input and 1 output', () => {
+      var tx = new Transaction()
+
+      const privateKeys = []
+
+      for (let i=0; i < 30; i++){
+        tx.from(simpleUTXO)
+        privateKeys.push(privateKey)
+      }
+
+      tx
+        .to('yeB49jSYYp3786GQr7eKFwLNdEqonBf6hm', 5460)
+        .change('yeB49jSYYp3786GQr7eKFwLNdEqonBf6hm')
+        .sign(privateKeys);
+
+      tx.isFullySigned().should.equal(true);
+
+      tx.getFee().should.gte(tx.toString().length/2);
+    });
+
+    it('should return correct minimal fee amount with 30 input and 30 outputs', () => {
+      var tx = new Transaction()
+
+      const privateKeys = []
+
+      for (let i=0; i < 30; i++){
+        tx.from(simpleUTXO)
+        privateKeys.push(privateKey)
+      }
+
+      for (let i=0; i < 30; i++){
+        tx.to('yeB49jSYYp3786GQr7eKFwLNdEqonBf6hm', 5460)
+      }
+
+      tx
+        .change('yeB49jSYYp3786GQr7eKFwLNdEqonBf6hm')
+        .sign(privateKeys);
+
+      tx.isFullySigned().should.equal(true);
+
+      tx.getFee().should.gte(tx.toString().length/2);
+    });
+
+    it('should return correct minimal fee amount with 30 input and 30 outputs with custom fee per KB', () => {
+      var tx = new Transaction()
+        .feePerKb(2000)
+
+      const privateKeys = []
+
+      for (let i=0; i < 30; i++){
+        tx.from(simpleUTXO)
+        privateKeys.push(privateKey)
+      }
+
+      for (let i=0; i < 30; i++){
+        tx.to('yeB49jSYYp3786GQr7eKFwLNdEqonBf6hm', 5460)
+      }
+
+      tx
+        .change('yeB49jSYYp3786GQr7eKFwLNdEqonBf6hm')
+        .sign(privateKeys);
+
+      tx.isFullySigned().should.equal(true);
+
+      tx.getFee().should.gte(tx.toString().length);
+    });
+  })
+
+
   describe('transaction creation test vector', function () {
     this.timeout(5000);
     var index = 0;
@@ -466,7 +573,7 @@ describe('Transaction', function () {
         .change(changeAddress)
         .sign(privateKey);
       transaction.outputs.length.should.equal(2);
-      transaction.outputs[1].satoshis.should.equal(49000);
+      transaction.outputs[1].satoshis.should.equal(49745);
       transaction.outputs[1].script
         .toString()
         .should.equal(Script.fromAddress(changeAddress).toString());
@@ -540,7 +647,7 @@ describe('Transaction', function () {
         .sign(privateKey);
       transaction._estimateSize().should.be.within(1000, 1999);
       transaction.outputs.length.should.equal(2);
-      transaction.outputs[1].satoshis.should.equal(34000);
+      transaction.outputs[1].satoshis.should.equal(37808);
     });
     it('if satoshis are invalid', function () {
       var transaction = new Transaction()
@@ -1126,7 +1233,7 @@ describe('Transaction', function () {
         .change(changeAddress)
         .to(toAddress, 10000);
       transaction.inputAmount.should.equal(100000000);
-      transaction.outputAmount.should.equal(99999000);
+      transaction.outputAmount.should.equal(99999745);
     });
     it('returns correct values for coinjoin transaction', function () {
       // see livenet tx c16467eea05f1f30d50ed6dbc06a38539d9bb15110e4b7dc6653046a3678a718
@@ -1216,7 +1323,7 @@ describe('Transaction', function () {
       tx.outputs.length.should.equal(2);
       tx.outputs[0].satoshis.should.equal(10000000);
       tx.outputs[0].script.toAddress().toString().should.equal(toAddress);
-      tx.outputs[1].satoshis.should.equal(89999000);
+      tx.outputs[1].satoshis.should.equal(89999745);
       tx.outputs[1].script.toAddress().toString().should.equal(changeAddress);
     });
   });