diff --git a/lib/Script.js b/lib/Script.js
index f611f74..1b5c77d 100644
--- a/lib/Script.js
+++ b/lib/Script.js
@@ -116,7 +116,6 @@ Script.prototype.isMultiSig = function() {
 };
 
 Script.prototype.isPubkeyHashScriptSig = function() {
-  // TODO: add more restrictions to chunks?
   return (this.chunks.length == 2 &&
     Buffer.isBuffer(this.chunks[0]) &&
     Buffer.isBuffer(this.chunks[1]));
@@ -423,6 +422,7 @@ Script.prototype.writeOp = function(opcode) {
   this.buffer = buf;
 
   this.chunks.push(opcode);
+  return this;
 };
 
 Script.prototype.writeN = function(n) {
diff --git a/test/test.Script.js b/test/test.Script.js
index 01d4f14..1de7c52 100644
--- a/test/test.Script.js
+++ b/test/test.Script.js
@@ -7,6 +7,7 @@ var should = chai.should();
 
 var ScriptModule = bitcore.Script;
 var Address = bitcore.Address;
+var Opcode = bitcore.Opcode;
 var networks = bitcore.networks;
 var Script;
 var testdata = testdata || require('./testdata');
@@ -116,12 +117,12 @@ describe('Script', function() {
     '0266dd7664e65958f3cc67bf92ad6243bc495df5ab56691719263977104b635bea',
     '02ee91377073b04d1d9d19597b81a7be3db6554bd7d16151cb5599a6107a589e70',
     '02c8f63ad4822ef360b5c300f08488fa0fa24af2b2bebb6d6b602ca938ee5af793'
-    ];
+  ];
 
   describe('#_sortKeys', function() {
     it('should get the pubkeys in properly sorted order', function() {
-      var pubs = testPubKeysHex.map( function(hex) { 
-        return new Buffer(hex,'hex');
+      var pubs = testPubKeysHex.map(function(hex) {
+        return new Buffer(hex, 'hex');
       });
       var sorted = Script._sortKeys(pubs);
       sorted[0].toString('hex').should.equal(testPubKeysHex[2]);
@@ -134,17 +135,19 @@ describe('Script', function() {
 
   describe('#createMultisig', function() {
     it('should create ', function() {
-      var pubs = testPubKeysHex.map( function(hex) {
-        return new Buffer(hex,'hex');
+      var pubs = testPubKeysHex.map(function(hex) {
+        return new Buffer(hex, 'hex');
       });
       // 3 of 5 multisig, unsorted
       // test case generated with: bitcoind createmultisig 3 '["02c525d65d18be8fb36ab50a21bee02ac9fdc2c176fa18791ac664ea4b95572ae0", "02b937d54b550a3afdc2819772822d25869495f9e588b56a0205617d80514f0758", "0266dd7664e65958f3cc67bf92ad6243bc495df5ab56691719263977104b635bea","02ee91377073b04d1d9d19597b81a7be3db6554bd7d16151cb5599a6107a589e70", "02c8f63ad4822ef360b5c300f08488fa0fa24af2b2bebb6d6b602ca938ee5af793"]'
-      var s1 = Script.createMultisig(3,pubs, {noSorting: true});
+      var s1 = Script.createMultisig(3, pubs, {
+        noSorting: true
+      });
       s1.getBuffer().toString('hex').should.equal('532102c525d65d18be8fb36ab50a21bee02ac9fdc2c176fa18791ac664ea4b95572ae02102b937d54b550a3afdc2819772822d25869495f9e588b56a0205617d80514f0758210266dd7664e65958f3cc67bf92ad6243bc495df5ab56691719263977104b635bea2102ee91377073b04d1d9d19597b81a7be3db6554bd7d16151cb5599a6107a589e702102c8f63ad4822ef360b5c300f08488fa0fa24af2b2bebb6d6b602ca938ee5af79355ae');
 
       // 3 of 5 multisig, sorted
       // test case generated with: bitcoind createmultisig 3 '["0266dd7664e65958f3cc67bf92ad6243bc495df5ab56691719263977104b635bea", "02b937d54b550a3afdc2819772822d25869495f9e588b56a0205617d80514f0758", "02c525d65d18be8fb36ab50a21bee02ac9fdc2c176fa18791ac664ea4b95572ae0", "02c8f63ad4822ef360b5c300f08488fa0fa24af2b2bebb6d6b602ca938ee5af793", "02ee91377073b04d1d9d19597b81a7be3db6554bd7d16151cb5599a6107a589e70"]'
-      var s2 = Script.createMultisig(3,pubs);
+      var s2 = Script.createMultisig(3, pubs);
       s2.getBuffer().toString('hex').should.equal('53210266dd7664e65958f3cc67bf92ad6243bc495df5ab56691719263977104b635bea2102b937d54b550a3afdc2819772822d25869495f9e588b56a0205617d80514f07582102c525d65d18be8fb36ab50a21bee02ac9fdc2c176fa18791ac664ea4b95572ae02102c8f63ad4822ef360b5c300f08488fa0fa24af2b2bebb6d6b602ca938ee5af7932102ee91377073b04d1d9d19597b81a7be3db6554bd7d16151cb5599a6107a589e7055ae');
 
     });
@@ -156,7 +159,7 @@ describe('Script', function() {
     it('should count missing signature in empty scripts', function() {
       var s = new Script();
       s.countMissingSignatures().should.equal(1);
-    }); 
+    });
     it('should count missing signatures p2sh 2-3 1 missing', function() {
       // from https://gist.github.com/matiu/11182987
       var b = new Buffer('00483045022100aac57f3ba004e6265097b759d92132c43fb5dcb033c2a3f6e61caa5e05e6b97e02200dae579e54c8e733d222eae5bbbaf557bbcf03271cf76775c91744c24a99916b014c69522103197599f6e209cefef07da2fddc6fe47715a70162c531ffff8e611cef23dfb70d210392dccb2ed470a45984811d6402fdca613c175f8f3e4eb8e2306e8ccd7d0aed032103e085eb6fa1f20b2722c16161144314070a2c316a9cae2489fd52ce5f63fff6e453ae', 'hex');
@@ -177,37 +180,66 @@ 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 pubs = testPubKeysHex.map(function(hex) {
+        return new Buffer(hex, 'hex');
+      });
+      var s1 = Script.createMultisig(3, pubs, {
+        noSorting: true
       });
-      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'));
+      (new Script(new Buffer('000000ae', 'hex'))).isMultiSig().should.equal(false);
+      var s = new Script(new Buffer('522103bb52138972c48a132fc1f637858c5189607dd0f7fe40c4f20f6ad65f2d389ba42103bb52138972c48a132fc1f637858c5189607dd0f7fe40c4f20f6ad65f2d389ba45f6054ae', 'hex'));
+
+      (new Script(new Buffer('522103bb52138972c48a132fc1f637858c5189607dd0f7fe40c4f20f6ad65f2d389ba42103bb52138972c48a132fc1f637858c5189607dd0f7fe40c4f20f6ad65f2d389ba45f6054ae', 'hex'))).isMultiSig().should.equal(false);
 
-      (new Script(new Buffer('522103bb52138972c48a132fc1f637858c5189607dd0f7fe40c4f20f6ad65f2d389ba42103bb52138972c48a132fc1f637858c5189607dd0f7fe40c4f20f6ad65f2d389ba45f6054ae','hex'))).isMultiSig().should.equal(false);
-      
     });
   });
-  describe('#isPubkeyHashScriptSig', function() {
-    var testPKHSS = function(raw, result) {
-      var s = new Script(new Buffer(raw, 'hex');
-      s.isPubkeyHashScriptSig().should.equal(result); 
+  describe.only('ScriptSig validations', function() {
+    var pkhss = '4730440220150eccaec1e5d9104434544bf820b1e24c94e0da7a768d62260b57b9f02877db02204d5d193e833099adb0bf38a610d314936fb70671383d2fa6e09586bc77abe3f9012103146226860c4f62b1ab79bdbb0d3145bf1dc1a0cfa7bf35f2aa30e8432717ac72'
+    var p2shss = '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'
+    var pkss = '0313220402bc01062f503253482f';
+    var msss = '004830450220582cd0d8c0f42113ef036af9b5b26d500447eb47dd737e129b0d1b9f870166fa022100e6794cc9158cb2347ff440cec6c017ab5043bb71f1cff55baf9df4888902e26a0149304602210089c912fa687304f82634fe4e02f86ad721c3f9b8a6e7a2c06a7b0ba7a891ac18022100ff4f47c88c752a9e2e1ad8d450c7d5c06628159ea2e614f260dcf28c1c7333b101483045022100dd0c15876575df2e9973f3cd57c4f5e9e84d94277d2f4d82cebfb10fe2b25d62022060eb86654f538a5e5c55288de828bdd854e5d1434050a6b54d7d5402b59528ae01';
+    var createTestF = function(f) {
+      var testF = function(raw, result) {
+        var s = new Script(new Buffer(raw, 'hex'));
+        f.bind(s)().should.equal(result);
+      };
+      return testF;
     };
-    it('should identify pubkeyhash scriptsig', function() {
-      testPKHSS(pkhss, true);
+    describe('#isPubkeyHashScriptSig', function() {
+      var isPubkeyHashScriptSig = new Script().isPubkeyHashScriptSig;
+      var testPKHSS = createTestF(isPubkeyHashScriptSig);
+      it('should identify pubkeyhash scriptsig', function() {
+        testPKHSS(pkhss, true);
+      });
+      it('should not identify pubkey scriptsig', function() {
+        testPKHSS(pkss, false);
+      });
+      it('should not identify p2sh scriptsig', function() {
+        testPKHSS(p2shss, false);
+      });
+      it('should not identify multisig scriptsig', function() {
+        testPKHSS(msss, false);
+      });
     });
-    it('should not identify pubkey scriptsig', function() {
-      testPKHSS(pkss, false);
+    describe('#isP2shScriptSig', function() {
+      var isP2shScriptSig = new Script().isP2shScriptSig;
+      var testP2SHSS = createTestF(isP2shScriptSig);
+      it('should not identify pubkeyhash scriptsig', function() {
+        testP2SHSS(pkhss, false);
+      });
+      it('should not identify pubkey scriptsig', function() {
+        testP2SHSS(pkss, false);
+      });
+      it('should identify p2sh scriptsig', function() {
+        testP2SHSS(p2shss, true);
+      });
+      it('should not identify multisig scriptsig', function() {
+        testP2SHSS(msss, false);
+      });
     });
-    it('should not identify p2sh scriptsig', function() {
-      testPKHSS(p2shss, false);
-    });
-    it('should not identify multisig scriptsig', function() {
-      testPKHSS(msss, false);
-    });
-  });
 
+  });
 });