Issue testing Laravel Controller with Mockery | trying to get property of non-object - unit-testing

Question

I'm very new to testing controllers and I'm running into a problem with a method(). I believe I'm either missing something in my test or my Controller / Repository is designed incorrectly.
The application I'm writing is basically one of those secure "one time" tools. Where you create a note, the system provides you with a URL, once that url is retrieved the note is deleted. I actually have the application written but I am going back to write tests for practice (I know that's backwards).
My Controller:
use OneTimeNote\Repositories\NoteRepositoryInterface as Note;
class NoteController extends \Controller {
protected $note;
public function __construct(Note $note)
{
$this->note = $note;
}
public function getNote($url_id, $key)
{
$note = $this->note->find($url_id, $key);
if (!$note) {
return \Response::json(array('message' => 'Note not found'), 404);
}
$this->note->delete($note->id);
return \Response::json($note);
}
...
I've injected my Note interface in to my controller and all is well.
My Test
use \Mockery as M;
class OneTimeNoteTest extends TestCase {
public function setUp()
{
parent::setUp();
$this->mock = $this->mock('OneTimeNote\Repositories\EloquentNoteRepository');
}
public function mock($class)
{
$mock = M::mock($class);
$this->app->instance($class, $mock);
return $mock;
}
public function testShouldReturnNoteObj()
{
// Should Return Note
$this->mock->shouldReceive('find')->once()->andReturn('test');
$note = $this->call('GET', '/note/1234567890abcdefg/1234567890abcdefg');
$this->assertEquals('test', $note->getContent());
}
}
...
The error I'm getting
1) OneTimeNoteTest::testShouldReturnNoteObj
ErrorException: Trying to get property of non-object
/Users/andrew/laravel/app/OneTimeNote/Controllers/NoteController.php:24
Line 24 is in reference to this line found in my controller:
$this->note->delete($note->id);
Basically my abstracted repository method delete() obviously can't find $note->id because it really doesn't exist in the testing environment. Should I create a Note within the test and try to actually deleting it? Or would that be something that should be a model test? As you can see I need help, thanks!
----- Update -----
I tried to stub the repository to return a Note object as Dave Marshall mentioned in his answer, however I'm now receiving another error.
1) OneTimeNoteTest::testShouldReturnNoteObj
BadMethodCallException: Method Mockery_0_OneTimeNote_Repositories_EloquentNoteRepository::delete() does not exist on this mock object
I do have a delete() method in my repository and I know it's working when I test my route in the browser.
public function delete($id)
{
Note::find($id)->delete();
}

Answer 1

You are stubbing the note repository to return a string, PHP is then trying to retrieve the id attribute of a string, hence the error.
You should stub the repository to return a Note object, something like:
$this->mock->shouldReceive('find')->once()->andReturn(new Note());

Answer 2

Building upon Dave's answer, I was able to figure out what my problem is. I wasn't mocking the delete() method. I didn't understand the need to mock each individual method in my controller that would be called.
I just added this line:
$mock->shouldReceive('delete')->once()->andReturnNull();
Since my delete method is just deleting the note after it is found, I went ahead and mocked it but set it to return null.