diff --git a/lib/script_interpreter.js b/lib/script_interpreter.js
index 952fc9b..88b1f0d 100644
--- a/lib/script_interpreter.js
+++ b/lib/script_interpreter.js
@@ -1045,6 +1045,16 @@ ScriptInterpreter.prototype.step = function() {
 }
 
 /**
+ * Verifies a Script by executing it and returns true if it is valid.
+ * This function needs to be provided with the scriptSig and the scriptPubkey
+ * separately.
+ * @param {Script} scriptSig - the script's first part (corresponding to the tx input)
+ * @param {Script} scriptPubkey - the script's last part (corresponding to the tx output)
+ * @param {Transaction} [tx] - the Transaction containing the scriptSig in one input (used
+ *    to check signature validity for some opcodes like OP_CHECKSIG)
+ * @param {number} nin - index of the transaction input containing the scriptSig verified.
+ * @param {number} flags - evaluation flags. See ScriptInterpreter.SCRIPT_* constants
+ *
  * Translated from bitcoind's VerifyScript
  */
 ScriptInterpreter.prototype.verify = function(scriptSig, scriptPubkey, tx, nin, flags) {
@@ -1054,6 +1064,9 @@ ScriptInterpreter.prototype.verify = function(scriptSig, scriptPubkey, tx, nin,
   if (_.isUndefined(nin)) {
     nin = 0;
   }
+  if (_.isUndefined(flags)) {
+    flags = 0;
+  }
   this.set({
     script: scriptSig,
     tx: tx,
diff --git a/test/script_interpreter.js b/test/script_interpreter.js
index 91220b1..085602a 100644
--- a/test/script_interpreter.js
+++ b/test/script_interpreter.js
@@ -202,7 +202,7 @@ describe('ScriptInterpreter', function() {
     var verified = interp.verify(scriptSig, scriptPubkey, spendtx, 0, flags);
     verified.should.equal(expected);
   };
-  describe('bitcoind fixtures', function() {
+  describe('bitcoind script evaluation fixtures', function() {
     var testAllFixtures = function(set, expected) {
       var c = 0;
       set.forEach(function(vector) {
@@ -221,13 +221,15 @@ describe('ScriptInterpreter', function() {
     testAllFixtures(script_valid, true);
     testAllFixtures(script_invalid, false);
 
+  });
+  describe.only('bitcoind transaction evaluation fixtures', function() {
     var c = 0;
     tx_valid.forEach(function(vector) {
       if (vector.length === 1) {
         return;
       }
       c++;
-      it.skip('should pass tx_valid vector ' + c, function() {
+      it('should pass tx_valid vector ' + c, function() {
         var inputs = vector[0];
         var txhex = vector[1];
         var flags = getFlags(vector[2]);
@@ -240,18 +242,18 @@ describe('ScriptInterpreter', function() {
           if (txoutnum === -1) {
             txoutnum = 0xffffffff; //bitcoind casts -1 to an unsigned int
           }
-          var txkey = txid + ':' + txoutnum;
-          map[txkey] = Script.fromBitcoindString(scriptPubKeyStr);
+          map[txid + ':' + txoutnum] = Script.fromBitcoindString(scriptPubKeyStr);
         });
 
         var tx = Transaction(txhex);
         tx.inputs.forEach(function(txin, j) {
+          console.log('input ' + j);
           var scriptSig = txin.script;
           var txidhex = txin.prevTxId.toString('hex');
           var txoutnum = txin.outputIndex;
-          var txkey = txidhex + ':' + txoutnum;
-          var scriptPubkey = map[txkey];
+          var scriptPubkey = map[txidhex + ':' + txoutnum];
           should.exist(scriptPubkey);
+          should.exist(scriptSig);
           var interp = ScriptInterpreter();
           var verified = interp.verify(scriptSig, scriptPubkey, tx, j, flags);
           verified.should.equal(true);