Added res.locals(obj) test

test/res.locals.js

@@ -0,0 +1,25 @@
+
+var express = require('../')
+  , request = require('./support/http');
+
+describe('res', function(){
+  describe('.locals(obj)', function(){
+    it('should merge locals', function(done){
+      var app = express();
+
+      app.use(function(req, res){
+        Object.keys(res.locals).should.eql([]);
+        res.locals({ user: 'tobi', age: 1 });
+        res.locals.user.should.equal('tobi');
+        res.locals.age.should.equal(1);
+        res.end();
+      });
+
+      request(app)
+      .get('/')
+      .end(function(res){
+        done();
+      })
+    })
+  })
+})