add more strict checking, plus tests

lib/Script.js

@@ -110,7 +110,7 @@ function isSmallIntOp(opcode) {
 Script.prototype.isMultiSig = function() {
   return (this.chunks.length > 3 &&
     isSmallIntOp(this.chunks[0]) &&
-    Buffer.isBuffer(this.chunks[1]) &&
+    this.chunks.slice(1,this.chunks.length-2).every(function(i){return Buffer.isBuffer(i);}) &&
     isSmallIntOp(this.chunks[this.chunks.length - 2]) &&
     this.chunks[this.chunks.length - 1] == Opcode.map.OP_CHECKMULTISIG);
 };

test/test.Script.js

@@ -175,5 +175,23 @@ describe('Script', function() {
   });
 
 
+  describe('#isMultiSig', function() {
+    it('should return true for valid multisig scripts', function() {
+      var pubs = testPubKeysHex.map( function(hex) {
+        return new Buffer(hex,'hex');
+      });
+      var s1 = Script.createMultisig(3,pubs, {noSorting: true});
+      s1.isMultiSig().should.equal(true);
+    });
+    it('should return false for invalid multisig scripts', function() {
+      (new Script(new Buffer('000000ae','hex'))).isMultiSig().should.equal(false);
+      var s = new Script(new Buffer('522103bb52138972c48a132fc1f637858c5189607dd0f7fe40c4f20f6ad65f2d389ba42103bb52138972c48a132fc1f637858c5189607dd0f7fe40c4f20f6ad65f2d389ba45f6054ae','hex'));
+
+console.log('[test.Script.js.189]',s.chunks); //TODO
+
+      (new Script(new Buffer('522103bb52138972c48a132fc1f637858c5189607dd0f7fe40c4f20f6ad65f2d389ba42103bb52138972c48a132fc1f637858c5189607dd0f7fe40c4f20f6ad65f2d389ba45f6054ae','hex'))).isMultiSig().should.equal(false);
+      
+    });
+  });
 
 });