public function testToString()
 {
     $group = $this->getMock('Oro\\Bundle\\UserBundle\\Entity\\Group');
     $user = $this->getMock('Oro\\Bundle\\UserBundle\\Entity\\User');
     // test when owner filled
     $this->entity->setOwner(true);
     $this->assertInternalType('string', $this->entity->__toString());
     $this->assertNotEmpty($this->entity->__toString());
     // clear owner
     $this->entity->setOwner(null);
     // test when email filled
     $this->entity->setEmail('test email');
     $this->assertInternalType('string', $this->entity->__toString());
     $this->assertNotEmpty($this->entity->__toString());
     // clear email
     $this->entity->setEmail(null);
     // test when users filled
     $this->entity->addUser($user);
     $this->assertInternalType('string', $this->entity->__toString());
     $this->assertNotEmpty($this->entity->__toString());
     // clear users
     $this->entity->getUsers()->clear();
     // test when groups filled
     $this->entity->addGroup($group);
     $this->assertInternalType('string', $this->entity->__toString());
     $this->assertNotEmpty($this->entity->__toString());
     // clear groups
     $this->entity->getGroups()->clear();
     // should be empty if nothing filled
     $this->assertEmpty($this->entity->__toString());
 }