public function testAddValidator()
 {
     $service = new ServiceProvider();
     // Initially empty
     $this->assertEmpty(Validator::$methods);
     $test_callback = function () {
         echo 'test';
     };
     $service->addValidator('awesome', $test_callback);
     $this->assertNotEmpty(Validator::$methods);
     $this->assertArrayHasKey('awesome', Validator::$methods);
     $this->assertContains($test_callback, Validator::$methods);
 }