diff --git a/copy-to.js b/copy-to.js
index 716a072..a45ee6e 100644
--- a/copy-to.js
+++ b/copy-to.js
@@ -42,10 +42,10 @@ CopyStreamQuery.prototype._transform = function(chunk, enc, cb) {
   var messageCode;
   var needPush = false;
 
-  while((chunk.length - offset) > (Byte1Len + Int32Len)) {
+  while((chunk.length - offset) >= (Byte1Len + Int32Len)) {
     var messageCode = chunk[offset]
 
-    //console.log(c, w, offset, 'PostgreSQL message ' + String.fromCharCode(messageCode))
+    //console.log('PostgreSQL message ' + String.fromCharCode(messageCode))
     switch(messageCode) {
 
       // detect COPY start
@@ -79,7 +79,7 @@ CopyStreamQuery.prototype._transform = function(chunk, enc, cb) {
     }
 
     length = chunk.readUInt32BE(offset+Byte1Len)
-    if(chunk.length > (offset + Byte1Len + length)) {
+    if(chunk.length >= (offset + Byte1Len + length)) {
       offset += Byte1Len + Int32Len
       if (needPush) {
         var row = chunk.slice(offset, offset + length - Int32Len)
diff --git a/test/copy-to.js b/test/copy-to.js
index 0982fc8..50bd7c8 100644
--- a/test/copy-to.js
+++ b/test/copy-to.js
@@ -7,6 +7,7 @@ var concat = require('concat-stream')
 var pg = require('pg')
 
 var copy = require('../').to
+var code = require('../message-formats')
 
 var client = function() {
   var client = new pg.Client()
@@ -22,6 +23,18 @@ var testConstruction = function() {
 
 testConstruction()
 
+var testComparators = function() {
+  var copy1 = copy();
+  copy1.pipe(concat(function(buf) {
+    assert(copy1._gotCopyOutResponse, 'should have received CopyOutResponse')
+    assert(!copy1._remainder, 'Message with no additional data (len=Int4Len+0) should not leave a remainder')
+  }))
+  copy1.end(new Buffer([code.CopyOutResponse, 0x00, 0x00, 0x00, 0x04])); 
+
+
+}
+testComparators();
+
 var testRange = function(top) {
   var fromClient = client()
   var txt = 'COPY (SELECT * from generate_series(0, ' + (top - 1) + ')) TO STDOUT'