diff --git a/.travis.yml b/.travis.yml
index 0391af3b..aeab0700 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -10,6 +10,14 @@ node_js:
 git:
   depth: 1
 
+matrix:
+  include:
+  - node_js: '0.10'
+    env: TEST_VERSION=compat
+  - node_js: '0.12'
+    env: TEST_VERSION=compat
+  - node_js: '4'
+    env: TEST_VERSION=compat
 #matrix:
   #fast_finish: true
   #allow_failures:
diff --git a/Readme.md b/Readme.md
index 74e2e898..80555d7a 100644
--- a/Readme.md
+++ b/Readme.md
@@ -422,6 +422,17 @@ To see the output from all of Socket.IO's debugging scopes you can use:
 DEBUG=socket.io* node myapp
 ```
 
+## Testing
+
+```
+npm test
+```
+This runs the `gulp` task `test`. By default the test will be run with the source code in `lib` directory.
+
+Set the environmental variable `TEST_VERSION` to `compat` to test the transpiled es5-compat version of the code.
+
+The `gulp` task `test` will always transpile the source code into es5 and export to `dist` first before running the test.
+
 ## License
 
 MIT
diff --git a/gulpfile.js b/gulpfile.js
index c0788c8d..c3734898 100644
--- a/gulpfile.js
+++ b/gulpfile.js
@@ -22,14 +22,15 @@ gulp.task('clean', function () {
   return del([TRANSPILE_DEST_DIR]);
 })
 
-gulp.task('test', function(){
+gulp.task('test', ['transpile'], function(){
   return gulp.src('test/socket.io.js', {read: false})
     .pipe(mocha({
       slow: 200,
-      reporter: 'dot',
+      reporter: 'spec',
       bail: true
     }))
-    .once('error', function () {
+    .once('error', function (err) {
+      console.error(err.stack);
       process.exit(1);
     })
     .once('end', function () {
@@ -37,6 +38,12 @@ gulp.task('test', function(){
     });
 });
 
+gulp.task('set-compat-node-env', function() {
+  process.env.TEST_VERSION = 'compat';
+});
+
+gulp.task('test-compat', ['set-compat-node-env', 'test']);
+
 gulp.task('istanbul-pre-test', function () {
   return gulp.src(['lib/**/*.js'])
     // Covering files
@@ -51,7 +58,8 @@ gulp.task('test-cov', ['istanbul-pre-test'], function(){
       reporter: 'dot'
     }))
     .pipe(istanbul.writeReports())
-    .once('error', function (){
+    .once('error', function (err){
+      console.error(err.stack);
       process.exit(1);
     })
     .once('end', function (){
diff --git a/test/socket.io.js b/test/socket.io.js
index eb1a8308..e9864746 100644
--- a/test/socket.io.js
+++ b/test/socket.io.js
@@ -1,6 +1,12 @@
-
+var testVersion = process.env.TEST_VERSION;
 var http = require('http').Server;
-var io = require('..');
+var io;
+if (testVersion === 'compat') {
+  console.log('testing compat version');
+  io = require('../dist');
+} else {
+  io = require('../lib');
+}
 var fs = require('fs');
 var join = require('path').join;
 var exec = require('child_process').exec;
@@ -426,9 +432,18 @@ describe('socket.io', function(){
   });
 
   describe('namespaces', function(){
-    var Socket = require('../lib/socket');
-    var Namespace = require('../lib/namespace');
-
+    var Socket;
+    if (testVersion === 'compat') {
+      Socket = require('../dist/socket');
+    } else {
+      Socket = require('../lib/socket');
+    }
+    var Namespace;
+    if (testVersion === 'compat') {
+      Namespace = require('../dist/namespace');
+    } else {
+      Namespace = require('../lib/namespace');
+    }
     it('should be accessible through .sockets', function(){
       var sio = io();
       expect(sio.sockets).to.be.a(Namespace);
@@ -651,7 +666,7 @@ describe('socket.io', function(){
         var clientSocket2 = client(srv);
         sio.on('connection', function() {
           connections++;
-          if(connections === 2) {
+          if (connections === 2) {
             done();
           }
         });
@@ -2036,7 +2051,12 @@ describe('socket.io', function(){
   });
 
   describe('middleware', function(done){
-    var Socket = require('../lib/socket');
+    var Socket;
+    if (testVersion === 'compat') {
+      Socket = require('../dist/socket');
+    } else {
+      Socket = require('../lib/socket');
+    }
 
     it('should call functions', function(done){
       var srv = http();