Add selected_db to the new redis instance if using client.duplicate

Author: Ruben Bridgewater

index.js

@@ -141,7 +141,9 @@ RedisClient.prototype.duplicate = function (options) {
     for (var elem in options) { // jshint ignore: line
         existing_options[elem] = options[elem];
     }
-    return new RedisClient(existing_options);
+    var client = new RedisClient(existing_options);
+    client.selected_db = this.selected_db;
+    return client;
 };
 
 RedisClient.prototype.initialize_retry_vars = function () {

test/node_redis.spec.js

@@ -44,7 +44,9 @@ describe("The node_redis client", function () {
 
                 describe('duplicate', function () {
                     it('check if all options got copied properly', function(done) {
+                        client.selected_db = 2;
                         var client2 = client.duplicate();
+                        assert.strictEqual(client2.selected_db, 2);
                         assert(client.connected);
                         assert(!client2.connected);
                         for (var elem in client.options) {