Zend 2: Unit tests for form class - zend-framework2

Question

I'm just starting using PHPUnit with Zend and need little help to figure out how these tests should work.
I want to test if form return any error message if I do not pass any POST parameters.
The problem is that one field from my form is using Doctrine's DoctrineModule\Form\Element\ObjectSelect
...
$this->add(array(
'type' => 'DoctrineModule\Form\Element\ObjectSelect',
'name' => 'user',
'attributes' => array(
'id' => 'user-label',
),
'options' => array(
'object_manager' => $em,
'target_class' => 'Application\Entity\User',
'property' => 'username',
'label' => 'User:',
'display_empty_item' => true,
'empty_item_label' => '---',
'label_generator' => function($entity) {
return $entity->getUsername();
},
),
));
...
I get following error:
Fatal error: Call to a member function getIdentifierFieldNames() on null
I tried override this field with mocked object, however Zend doesn't allow objects in type, just class name (string), so this code doesn't work:
public function testIfFormIsValid()
{
$objectSelect = $this->getMockBuilder('DoctrineModule\Form\Element\ObjectSelect')
->disableOriginalConstructor()
->getMock();
$objectSelect->expects($this->any())
->method('getValueOptions')
->will($this->returnValue(array()));
$form = new \AppModuleComment\Form\Comment('form', array(
'em' => $this->em // Mocked object
));
$form->add(array(
'type' => $objectSelect,
'name' => 'user',
'attributes' => array(
'id' => 'user-label',
),
'options' => array(
'object_manager' => $this->em,
'target_class' => 'Application\Entity\User',
'property' => 'username',
'label' => 'User:',
'display_empty_item' => true,
'empty_item_label' => '---',
'label_generator' => function($entity) {
return $entity->getUsername();
},
),
));
$data = array(
'id' => null,
'user' => null
);
$form->setData($data);
$this->assertTrue($form->isValid(), 'Form is not valid');
}
What am I doing wrong? How should I test such code?

Answer 1

It seems you are testing functionality of Zend or Doctrine (or both) and not your own code. When you use libraries you should trust these libraries.
What happens is: Form\Form::add() uses Form\Factory::create() to create from the array an element. Form\Factory::create() uses Form\FormElementManager::get() to get an element from the given type.
Your type is an object and because Form\FormElementManager::get() can not handle objects your script will fail.
It seems you want to test that if post is empty Form::valid() calls ObjectSelect::valid() but this does not verify if the value is null. That's code from Doctrine / Zend not yours. Don't test it.
More interesting it gets when you want to mock the result of an select from within Doctrines ObjectSelect. But that's another question.