start on Tune::merge()

src/Domain/Core/Tune.php

@@ -273,7 +273,22 @@ class Tune implements EntityInterface
      */
     protected function set($attribute, $value)
     {
-        call_user_func([$this, 'set'.$attribute], [$value]);
+        switch ($attribute) {
+            case 'index':
+                call_user_func([$this, 'set'.$attribute], $value);
+                break;
+
+            default:
+                $this->append($attribute, $value);
+        }
+    }
+
+    protected function append($attribute, array $values)
+    {
+        $method = 'add' . substr($attribute, 0, -1);
+        foreach ($values as $value) {
+            call_user_func([$this, $method], $value);
+        }
     }
 
     /**
@@ -320,4 +335,11 @@ class Tune implements EntityInterface
 
         return $this;
     }
+
+    public function merge(Tune $source)
+    {
+        //TODO
+        $this->titles = array_merge($this->getTitles(), $source->getTitles());
+        return $this;
+    }
 }