Ergo\Registry::isRegistered PHP Method

    public function isRegistered($key)
    {
        return isset($this->_registry[$key]);
    }

 public function testTriggerOnMissWithClosure()
 {
     $callcount = 0;
     $registry = new Registry();
     $registry->trigger('my_key', function ($registry) use(&$callcount) {
         $registry->register('my_key', (object) array('test' => 'blargh'));
         $callcount++;
     });
     $this->assertEquals($callcount, 0);
     $this->assertFalse($registry->isRegistered('my_key'));
     $this->assertEquals($registry->lookup('my_key')->test, 'blargh');
     $this->assertEquals($callcount, 1);
     $this->assertEquals($registry->lookup('my_key')->test, 'blargh');
     $this->assertEquals($callcount, 1);
 }