I want to test a action inside a zf2 controller that takes a file and process it. I tried the following code for reacting on post data:

```
public function testIndexActionCanBeAccessed()
{
    $this->dispatch('/', 'POST', array('test_file' => 'abcdefgh'));
    $this->assertResponseStatusCode(200);
}

```

The problem ist that the 'test\_file' paramater is handled as post parameter. So my question is, how can i achieve that php/zf2 handles the parameter as a file and not as a post paramater?

I tried to find an answer in the zf2 documentation and in the file 'Zend\Test\PHPUnit\Controller\AbstractHttpControllerTestCase' without success.