diff --git a/lib/cartodb/models/cdb_request.js b/lib/cartodb/models/cdb_request.js
index ec2da747..db5c93ea 100644
--- a/lib/cartodb/models/cdb_request.js
+++ b/lib/cartodb/models/cdb_request.js
@@ -1,25 +1,25 @@
 function CdbRequest() {
+    this.RE_USER_FROM_HOST = new RegExp(global.environment.user_from_host ||
+            '^([^\\.]+)\\.' // would extract "strk" from "strk.cartodb.com"
+    );
 }
 
 module.exports = CdbRequest;
 
-var RE_USER_FROM_HOST = new RegExp(global.environment.user_from_host ||
-        '^([^\\.]+)\\.' // would extract "strk" from "strk.cartodb.com"
-);
 
 CdbRequest.prototype.userByReq = function(req) {
     var host = req.headers.host;
     if (req.params.user) {
         return req.params.user;
     }
-    var mat = host.match(RE_USER_FROM_HOST);
+    var mat = host.match(this.RE_USER_FROM_HOST);
     if ( ! mat ) {
-        console.error("Pattern '" + RE_USER_FROM_HOST + "' does not match hostname '" + host + "'");
+        console.error("Pattern '" + this.RE_USER_FROM_HOST + "' does not match hostname '" + host + "'");
         return;
     }
     // console.log("Matches: "); console.dir(mat);
     if ( mat.length !== 2 ) {
-        console.error("Pattern '" + RE_USER_FROM_HOST + "' gave unexpected matches against '" + host + "': ", mat);
+        console.error("Pattern '" + this.RE_USER_FROM_HOST + "' gave unexpected matches against '" + host + "': ", mat);
         return;
     }
     return mat[1];
diff --git a/test/unit/cartodb/cdb_request.test.js b/test/unit/cartodb/cdb_request.test.js
new file mode 100644
index 00000000..04b2c1b9
--- /dev/null
+++ b/test/unit/cartodb/cdb_request.test.js
@@ -0,0 +1,60 @@
+require('../../support/test_helper');
+var assert = require('assert');
+
+var CdbRequest = require('../../../lib/cartodb/models/cdb_request');
+
+describe('req2params', function() {
+
+    function createRequest(host, userParam) {
+        var req = {
+            params: {},
+            headers: {
+                host: host
+            }
+        };
+
+        if (userParam) {
+            req.params.user = userParam;
+        }
+
+        return req;
+    }
+
+    it('extracts name from host header', function() {
+        var cdbRequest = new CdbRequest();
+        var user = cdbRequest.userByReq(createRequest('localhost'));
+
+        assert.equal(user, 'localhost');
+    });
+
+    it('extracts name from subdomain host header in case of no config', function() {
+        var userFromHostConfig = global.environment.user_from_host;
+        global.environment.user_from_host = null;
+
+        var cdbRequest = new CdbRequest();
+        var user = cdbRequest.userByReq(createRequest('development.localhost.lan'));
+
+        global.environment.user_from_host = userFromHostConfig;
+
+        assert.equal(user, 'development');
+    });
+
+    it('considers user param before headers', function() {
+        var cdbRequest = new CdbRequest();
+        var user = cdbRequest.userByReq(createRequest('localhost', 'development'));
+
+        assert.equal(user, 'development');
+    });
+
+    it('returns undefined when it cannot extract username', function() {
+        var userFromHostConfig = global.environment.user_from_host;
+        global.environment.user_from_host = null;
+
+        var cdbRequest = new CdbRequest();
+        var user = cdbRequest.userByReq(createRequest('localhost'));
+
+        global.environment.user_from_host = userFromHostConfig;
+
+        assert.equal(user, undefined);
+    });
+});