How to mock laravel model relathipship? - laravel

Question

I have a model that has a relationship with a View, that is complicate to popolate for make the feature test, but in the same time this is called from some component that are inside the controller called.
The following code is an example:
<?php
namespace App\Models;
use Illuminate\Database\Eloquent\Model;
use App\Models\TemperatureView;
class Town extends Model
{
function temperature()
{
return $this->hasOne(TemperatureView::class);
}
}
This is an example of the controller:
<?php
namespace App\Http\Controllers;
use App\Models\Town;
class TownController extends Controller
{
public function update($id)
{
// Here is the validation and update of Town model
$UpdatedTown = Town::where('id',$id);
$UpdatedTown->update($data);
$this->someOperation($UpdatedTown);
}
private function someOperation($Town)
{
//Here there is some operation that use the temperature Relationship
/*
Example:
$Town->temperature->value;
*/
}
}
The test is like is like this:
<?php
namespace Tests\Feature;
use Illuminate\Foundation\Testing\RefreshDatabase;
use Illuminate\Foundation\Testing\WithoutMiddleware;
use Tests\TestCase;
use App\Models\TownModel;
use Mockery;
use Mockery\MockInterface;
class TownTest extends TestCase
{
/**
* A basic test example.
*
* #return void
*/
public function test_get_town_temperature()
{
$payload = ['someTownInformation' => 'Value'];
$response = $this->post('/Town/'.$idTown,$payload);
$response->assertStatus(200);
//This test failed
}
public function test_get_town_temperature_with_mocking()
{
$this->instance(
TownModel::class,
Mockery::mock(TownModel::class, function (MockInterface $mock) {
$MockDataTemperature = (object) array('value'=>2);
$mock->shouldReceive('temperature')->andReturn($MockDataTemperature);
})
);
$payload = ['someTownInformation' => 'Value'];
$response = $this->post('/Town/'.$idTown,$payload);
$response->assertStatus(200);
//This test also failed
}
}
The first test failed because the Controller has some check on the relationship temperature, that is empty because the view on database is empty.
The second test failed also for the same reason. I tried to follow some others questions with the official guide of Laravel Mocking. I know this is mocking object and not specially Eloquent.
Is something I'm not setting well?
If it's not possible to mock only the function, is possible to mock all the relationship of view, bypassing the DB access to that?
Edit
I undestand that the mocking work only when the class is injected from laravel, so what I wrote above it's not pratical.
I don't know if it's possible to mock only it, I saw a different option, that to create the interface of the model and change for the test, but I didn't want to make it.