diff --git a/composer.json b/composer.json
index 940919e..c648e64 100644
--- a/composer.json
+++ b/composer.json
@@ -16,7 +16,7 @@
     "scripts": {
         "test": [
             "find src -name '*.php' -exec php -l {} \\;",
-            "./vendor/bin/phpunit --bootstrap vendor/autoload.php tests/BaseMediatorTest"
+            "./vendor/bin/phpunit --bootstrap vendor/autoload.php tests"
         ]
     },
     "autoload": {
diff --git a/src/BaseMediator.php b/src/BaseMediator.php
index fffe868..611210c 100644
--- a/src/BaseMediator.php
+++ b/src/BaseMediator.php
@@ -2,15 +2,8 @@
 namespace montefuscolo;
 
 class BaseMediator {
-    private static $instance = null;
     private $filters = null;
     private $actions = null;
-    private $prefix = 'root:';
-
-    private function __construct() {
-        $this->filters = array();
-        $this->actions = array();
-    }
 
     private function add(&$chain, $name, $callback, $priority) {
         if (empty($chain[ $name ])) {
@@ -40,6 +33,7 @@ private function run(&$chain, $name, $subject=null) {
             return $subject;
         }
 
+        $result = null;
         $filtering = $this->filters === $chain;
         $subject = array_slice(func_get_args(), 2);
 
@@ -56,18 +50,12 @@ private function run(&$chain, $name, $subject=null) {
             }
         }
 
-        return $subject;
+        return $result;
     }
 
-    private function get_hook_name($name) {
-        return $this->prefix . $name;
-    }
-
-    public static function getInstance() {
-        if (self::$instance === null) {
-            self::$instance = new self();
-        }
-        return self::$instance;
+    public function __construct() {
+        $this->filters = array();
+        $this->actions = array();
     }
 
     public function add_filter($name, $callback, $priority=10) {
@@ -87,33 +75,10 @@ public function remove_action($name, $func=null) {
     }
 
     public function run_filters($name, $subject=null) {
-        if (empty($this->filters[ $name ])) {
-            return $subject;
-        }
-
-        usort($this->filters[ $name ], function($a, $b) {
-            return $a[1] === $b[1] ? 0 : ( $a[1] < $b[1] ? -1 : 1 ); 
-        });
-
-        foreach ($this->filters[ $name ] as $function) {
-            list($callback, $priority) = $function;
-            $subject = call_user_func($callback, $subject);
-        }
-        return $subject;
+        return $this->run($this->filters, $name, $subject);
     }
 
     public function run_actions($name, $subject=null) {
-        if (empty($this->actions[ $name ])) {
-            return $subject;
-        }
-
-        usort($this->actions[ $name ], function($a, $b) {
-            return $a[1] === $b[1] ? 0 : ( $a[1] < $b[1] ? -1 : 1 ); 
-        });
-
-        foreach ($this->actions[ $name ] as $function) {
-            list($callback, $priority) = $function;
-            call_user_func($callback, $subject);
-        }
+        return $this->run($this->actions, $name, $subject);
     }
 }
diff --git a/src/SingletonMediator.php b/src/SingletonMediator.php
new file mode 100644
index 0000000..b8e9ac1
--- /dev/null
+++ b/src/SingletonMediator.php
@@ -0,0 +1,17 @@
+<?php
+namespace montefuscolo;
+
+class SingletonMediator extends BaseMediator {
+    private static $instance = null;
+
+    private function __construct() {
+        parent::__construct();
+    }
+
+    public static function getInstance() {
+        if (self::$instance === null) {
+            self::$instance = new self();
+        }
+        return self::$instance;
+    }
+}
diff --git a/tests/BaseMediatorTest.php b/tests/BaseMediatorTest.php
index 6a7c31e..23cb851 100644
--- a/tests/BaseMediatorTest.php
+++ b/tests/BaseMediatorTest.php
@@ -5,106 +5,106 @@
 
 
 class BaseMediatorTest extends TestCase {
-    
-    public function testUniqueInstance() {
-        $instance1 = BaseMediator::getInstance();
-        $instance2 = BaseMediator::getInstance();
-
-        $this->assertSame($instance1, $instance2);
-        $this->assertEquals($instance1, $instance2);
+    public function getInstance() {
+        return new BaseMediator();
     }
 
     public function testAddAction() {
         $self = $this;
 
-        $hooks = BaseMediator::getInstance();
-        $hooks->add_action('test_add_action', function() use ($self) {
+        $mediator = $this->getInstance();
+        $mediator->add_action('test_add_action', function() use ($self) {
             $self->assertTrue(true);
         });
 
-        $hooks->run_actions('test_add_action');
+        $mediator->run_actions('test_add_action');
     }
 
     public function testAddActionWithParameters() {
         $self = $this;
 
-        $hooks = BaseMediator::getInstance();
-        $hooks->add_action('test_addaction_with_parameters', function($subject) use ($self) {
+        $mediator = $this->getInstance();
+        $mediator->add_action('test_addaction_with_parameters', function($subject) use ($self) {
             $self->assertEquals('the-parameter', $subject);
         });
 
-        $hooks->run_actions('test_addaction_with_parameters', 'the-parameter');
+        $mediator->run_actions('test_addaction_with_parameters', 'the-parameter');
     }
 
-
     public function testAddActionPriority() {
-        $hooks = BaseMediator::getInstance();
+        $mediator = $this->getInstance();
         $state = (object) array('name' => '');
 
-        $hooks->add_action('test_add_action_priority', function($subject) {
+        $mediator->add_action('test_add_action_priority', function($subject) {
             $subject->name .= '1';
         }, 20);
 
-        $hooks->add_action('test_add_action_priority', function($subject) {
+        $mediator->add_action('test_add_action_priority', function($subject) {
             $subject->name .= '2';
         }, 10);
 
-        $hooks->add_action('test_add_action_priority', function($subject) {
+        $mediator->add_action('test_add_action_priority', function($subject) {
             $subject->name .= '3';
         }, 30);
 
-        $hooks->run_actions('test_add_action_priority', $state);
+        $mediator->run_actions('test_add_action_priority', $state);
         $this->assertEquals('213', $state->name);
     }
 
     public function testRemoveAction() {
-        $hooks = BaseMediator::getInstance();
+        $mediator = $this->getInstance();
 
         $callback1 = function($subject) { $subject->name .= 'callback1'; };
-        $hooks->add_action('test_remove_action', $callback1, 10);
+        $mediator->add_action('test_remove_action', $callback1, 10);
 
         $callback2 = function($subject) { $subject->name .= 'callback2'; };
-        $hooks->add_action('test_remove_action', $callback2, 20);
+        $mediator->add_action('test_remove_action', $callback2, 20);
 
         $state = (object) array('name' => '');
-        $hooks->run_actions('test_remove_action', $state);
+        $mediator->run_actions('test_remove_action', $state);
         $this->assertEquals('callback1callback2', $state->name);
 
         $state = (object) array('name' => '');
-        $hooks->remove_action('test_remove_action', $callback1);
-        $hooks->run_actions('test_remove_action', $state);
+        $mediator->remove_action('test_remove_action', $callback1);
+        $mediator->run_actions('test_remove_action', $state);
         $this->assertEquals('callback2', $state->name);
     }
 
     public function testEmptyAction() {
-        $hooks = BaseMediator::getInstance();
+        $mediator = $this->getInstance();
 
         $callback1 = function($subject) { $subject->name .= 'callback1'; };
-        $hooks->add_action('test_empty_action', $callback1, 10);
+        $mediator->add_action('test_empty_action', $callback1, 10);
 
         $callback2 = function($subject) { $subject->name .= 'callback2'; };
-        $hooks->add_action('test_empty_action', $callback2, 20);
+        $mediator->add_action('test_empty_action', $callback2, 20);
 
         $state = (object) array('name' => 'untouched');
-        $hooks->remove_action('test_empty_action');
-        $hooks->run_actions('test_empty_action', $state);
+        $mediator->remove_action('test_empty_action');
+        $mediator->run_actions('test_empty_action', $state);
         $this->assertEquals('untouched', $state->name);
     }
 
     public function testAddFilter() {
-        $hooks = BaseMediator::getInstance();
+        $mediator = $this->getInstance();
 
-        $hooks->add_filter('test_add_filter', function($subject){
+        $mediator->add_filter('test_add_filter', function($subject){
             return $subject * 2;
         });
-        $hooks->add_filter('test_add_filter', function($subject){
+        $mediator->add_filter('test_add_filter', function($subject){
             return $subject * 3;
         });
-        $hooks->add_filter('test_add_filter', function($subject){
+        $mediator->add_filter('test_add_filter', function($subject){
             return $subject - 6;
         });
 
-        $result = $hooks->run_filters('test_add_filter', 1);
+        $result = $mediator->run_filters('test_add_filter', 1);
         $this->assertEquals(0, $result);
     }
+
+    public function testRunEmptyFilter() {
+        $mediator = $this->getInstance();
+        $result = $mediator->run_filters('test_run_empty_filter', 'untouched');
+        $this->assertEquals('untouched', $result);
+    }
 }
diff --git a/tests/SingletonMediatorTest.php b/tests/SingletonMediatorTest.php
new file mode 100644
index 0000000..84cdac5
--- /dev/null
+++ b/tests/SingletonMediatorTest.php
@@ -0,0 +1,24 @@
+<?php
+
+use PHPUnit\Framework\TestCase;
+use montefuscolo\SingletonMediator;
+
+
+class SingletonMediatorTest extends BaseMediatorTest {
+    public function getInstance() {
+        return SingletonMediator::getInstance();
+    }
+
+    public function testUniqueInstance() {
+        $instance1 = $this->getInstance();
+        $instance2 = $this->getInstance();
+
+        $instance1->add_filter('test_unique_instance', function($value) {
+            return "> $value <";
+        });
+        $result = $instance2->run_filters('test_unique_instance', 'foo');
+
+        $this->assertSame($instance1, $instance2);
+        $this->assertEquals("> foo <", $result);
+    }
+}