diff --git a/index.js b/index.js
index 6b4370912..0f46765fe 100644
--- a/index.js
+++ b/index.js
@@ -102,13 +102,14 @@ var _engine = {
                 }
             });
     },
-    express: function(renderOption) {
-        renderOption = renderOption || {};
+    express: function(opts) {
+        opts = opts || {};
         var self = this;
-        return function(filePath, options, callback) {
-            assert(_.isArray(this.root), 'illegal views root, are you using express.js?');
-            renderOption.root = this.root;
-            self.renderFile(filePath, options, renderOption)
+        return function(filePath, ctx, callback) {
+            assert(_.isArray(this.root) || _.isString(this.root), 
+                   'illegal views root, are you using express.js?');
+            opts.root = this.root;
+            self.renderFile(filePath, ctx, opts)
                 .then(html => callback(null, html))
                 .catch(e => callback(e));
         };
diff --git a/src/express.js b/src/express.js
deleted file mode 100644
index 208fb5bdc..000000000
--- a/src/express.js
+++ /dev/null
@@ -1,19 +0,0 @@
-const Liquid = require('..');
-
-module.exports = function() {
-    var engine = Liquid({
-        root: '/root/',
-        extname: '.html'
-    });
-
-    function express(filePath, options, callback) {
-        fs.readFile(filePath, function(err, content) {
-            if (err) return callback(new Error(err));
-            // this is an extremely simple template engine
-            var rendered = content.toString().replace('#title#', '<title>' + options.title + '</title>')
-                .replace('#message#', '<h1>' + options.message + '</h1>');
-            return callback(null, rendered);
-        });
-    }
-    return express;
-};
diff --git a/test/express.js b/test/express.js
index 19b5cd2f3..aadb14adf 100644
--- a/test/express.js
+++ b/test/express.js
@@ -8,38 +8,29 @@ const Liquid = require('..');
 describe('engine#express()', function() {
     var app, engine;
 
-    before(function() {
-        mock({
-            '/root/foo.html': 'foo',
-            '/views/name.html': 'My name is {{name}}.',
-            '/views/include.html': '{% include file %}',
-            '/partials/bar.html': 'bar'
-        });
+    beforeEach(function() {
         app = express();
         engine = Liquid({
             root: '/root',
             extname: '.html'
         });
 
-        app.set('views', ['/views', '/partials']);
         app.set('view engine', 'html');
         app.engine('html', engine.express());
 
-        app.get('/name', function(req, res) {
-            res.render('name', {
-                name: 'harttle'
-            });
-        });
-        app.get('/include/:file', function(req, res) {
-            res.render('include', {
-                file: req.params.file
-            });
-        });
+        app.get('/name', (req, res) => res.render('name', {
+            name: 'harttle'
+        }));
+        app.get('/include/:file', (req, res) => res.render('include', {
+            file: req.params.file
+        }));
     });
-    after(function(){
+    after(function() {
         mock.restore();
     });
-    it('should render templates', function(done) {
+    it('should render express views', function(done) {
+        mock({ '/views/name.html': 'My name is {{name}}.' });
+        app.set('views', ['/views']);
         request(app).get('/name')
             .expect('My name is harttle.')
             .expect(200, done);
@@ -51,22 +42,51 @@ describe('engine#express()', function() {
         var file = '/not-exist.html';
         var ctx = {};
         engine.express().call(view, file, ctx, function(err) {
-            try{
+            try {
                 expect(err.code).to.equal('ENOENT');
                 expect(err.message).to.match(/Failed to lookup/);
                 done();
-            }
-            catch(e){
+            } catch (e) {
                 done(e);
             }
         });
     });
     it('should respect root option when lookup', function(done) {
+        mock({
+            '/root/foo.html': 'foo',
+            '/views/include.html': '{% include file %}'
+        });
+        app.set('views', ['/views']);
         request(app).get('/include/foo')
             .expect('foo')
             .expect(200, done);
     });
-    it('should respect express settings.views when lookup', function(done) {
+    it('should respect express views (Array) when lookup', function(done) {
+        mock({
+            '/views/include.html': '{% include file %}',
+            '/partials/bar.html': 'bar'
+        });
+        app.set('views', ['/views', '/partials']);
+        request(app).get('/include/bar')
+            .expect('bar')
+            .expect(200, done);
+    });
+    it('should respect express views (String) when lookup', function(done) {
+        mock({
+            '/views/include.html': '{% include file %}',
+            '/views/bar.html': 'bar'
+        });
+        app.set('views', '/views');
+        request(app).get('/include/bar')
+            .expect('bar')
+            .expect(200, done);
+    });
+    it('should respect express views (Undefined) when lookup', function(done) {
+        var files = {};
+        files[process.cwd() + '/views/include.html'] = '{% include file %}';
+        files[process.cwd() + '/views/bar.html'] = 'bar';
+        mock(files);
+
         request(app).get('/include/bar')
             .expect('bar')
             .expect(200, done);
diff --git a/test/liquid.js b/test/liquid.js
index e478df69a..92662ddb9 100644
--- a/test/liquid.js
+++ b/test/liquid.js
@@ -139,10 +139,13 @@ describe('liquid', function() {
     });
     describe('cache', function() {
         it('should be disabled by default', function() {
-            mock({
-                '/root/files/foo.html': 'bar'
-            });
-            return engine.renderFile('files/foo', ctx).should.eventually.equal('bar');
+            return engine.renderFile('files/foo')
+                .then(x => expect(x).to.equal('foo'))
+                .then(x => mock({
+                    '/root/files/foo.html': 'bar'
+                }))
+                .then(x => engine.renderFile('files/foo'))
+                .then(x => expect(x).to.equal('bar'));
         });
         it('should respect cache=true option', function() {
             engine = Liquid({
@@ -150,19 +153,13 @@ describe('liquid', function() {
                 extname: '.html',
                 cache: true
             });
-            return engine.renderFile('files/foo', ctx)
-                .then((result) => {
-                    return expect(result).to.equal('foo');
-                })
-                .then((result) => {
-                    mock({
-                        '/root/files/foo.html': 'bar'
-                    });
-                    return engine.renderFile('files/foo', ctx);
-                })
-                .then((result) => {
-                    return expect(result).to.equal('foo');
-                });
+            return engine.renderFile('files/foo')
+                .then(x => expect(x).to.equal('foo'))
+                .then(x => mock({
+                    '/root/files/foo.html': 'bar'
+                }))
+                .then(x => engine.renderFile('files/foo'))
+                .then(x => expect(x).to.equal('foo'));
         });
     });
 });
diff --git a/test/util/underscore.js b/test/util/underscore.js
index 91e0a112f..0cb39ee5f 100644
--- a/test/util/underscore.js
+++ b/test/util/underscore.js
@@ -54,7 +54,7 @@ describe('util/underscore', function() {
         });
     });
     describe('.echo()', function(){
-        it('should be transparent when called', function() {
+        it('should be transparent', function() {
             expect(_.echo('foo')('bar')).to.equal('bar');
         });
         it('should log the arguments', function() {