PHP - No dynamic implementing interfaces

For developing a little framework I tried to implement interfaces dynamically. But the idea to use the reflection api and the magic method __get does not work. It is not invoked, the compiler breaks before with:

Fatal error: Class Test contains 2 abstract methods and must therefore be declared abstract or implement the remaining methods

interface IA {
  public  function getA();
}

interface IB  {
  public  function getB();
}

class Aimpl {
  public  function getA() {
    echo "A";
  }
}

class Bimpl {
  public  function getB(){
    echo "B";
  }
}

class Test implements IA, IB {

  public function __call($name, $arguments) {
    
    $class = new ReflectionClass($this);
    $interfaces = $class->getInterfaces();

    $found = false;
    foreach ($interfaces as $iname => $interface) {
 
      $methods = $interface->getMethods();
      foreach ($methods as $method) {
        if($name == $method->name) {
          $found = true;
   // find the implementation
        }
      }
    }

    if(!$found) {
      throw new Exception("Method not found");
    }
  }
}

$test = new Test();
$test->getA();