invalid script test passing!

Script.js

@@ -33,11 +33,9 @@ function Script(buffer) {
   } else {
     this.buffer = util.EMPTY_BUFFER;
   }
-  console.log(buffertools.toHex(this.buffer));
   this.chunks = [];
   this.parse();
-  console.log(this.chunks);
-};
+}
 this.class = Script;
 
 Script.TX_UNKNOWN = TX_UNKNOWN;

ScriptInterpreter.js

@@ -811,7 +811,7 @@ ScriptInterpreter.prototype.stackTop = function stackTop(offset) {
 };
 
 ScriptInterpreter.prototype.stackBack = function stackBack() {
-  return this.stack[-1];
+  return this.stack[this.stack.length -1];
 };
 
 /**
@@ -944,7 +944,8 @@ function verifyStep3(scriptSig, scriptPubKey, txTo, nIn,
     return;
   }
 
-  assert.notEqual(siCopy.length, 0);
+  if (siCopy.length === 0)
+    throw new Error('siCopy should  have length != 0');
 
   var subscript = new Script(siCopy.stackPop());
 

test/test.ScriptInterpreter.js

@@ -31,19 +31,17 @@ describe('ScriptInterpreter', function() {
       var scriptPubKey = datum[1]; // output script
       var human = scriptSig + ' ' + scriptPubKey;
       it('should ' + (!valid ? 'not ' : '') + 'validate script ' + human, function(done) {
-        console.log((!valid ? 'invalid ' : 'valid ') + human + ';' + (i++) + ' - ' + datum[2]);
         try {
-          ScriptInterpreter.verify(
-            Script.fromHumanReadable(scriptSig),
-            Script.fromHumanReadable(scriptPubKey),
-            null, 0, 0, // tx, output index, and hashtype
+          ScriptInterpreter.verifyFull(
+            Script.fromHumanReadable(scriptSig), // scriptSig
+            Script.fromHumanReadable(scriptPubKey), // scriptPubKey
+            null, 0, 0, // tx, output index, hashtype
+            { verifyP2SH: !valid}, // only verify P2SH for invalid data set
             function(err, result) {
               if (valid) {
                 should.not.exist(err);
               } else {
                 var failed = (typeof err !== 'undefined') || (result === false);
-                console.log('err=' + err);
-                console.log('result=' + result);
                 failed.should.equal(true);
               }
               if (typeof result !== 'undefined') {

test/test.examples.js

@@ -15,8 +15,8 @@ var examples = [
 ];
 
 describe('Examples', function() {
-  //before(mute);
-  //after(unmute);
+  before(mute);
+  after(unmute);
   examples.forEach(function(example) {
     it('valid '+example, function() {
       var ex = require('../examples/'+example);