Test Model From Job Class PHPUnit Mockery

How do I mock the markshipped method on the ebayOrders model? I am testing that the job handle() method works correctly. My current test the markshipped method still runs.

Job -

class ProcessOrderJob implements ShouldQueue
{
public function handle()
    {
        $DB = '';
        $Controller = '';
        if (strcmp($this->username, 'user1') === 0) {
            $DB = '\App\user1orders';
            
        } elseif (strcmp($this->username, 'user2') === 0) {
            $DB = '\App\user2orders';
            
        }

        while ($DB::all()->isNotEmpty()) {
            $order = $DB::first();

            $multiple_orders = $order->getOtherOrders();

            $processboxhelper = new ProcessBoxHelper();

            if ($multiple_orders->count() > 1) {
                $multiple_orders->push($order);

                if ($processboxhelper->process($multiple_orders)) {
                    $multiple_orders->map(function ($single_order) {
                        $response = $single_order->markShipped();
                        // $response = ['success' => true, 'ShippedTime' => now()];
                        if ($response['success']) {
                            $single_order->ShippedTime = $response['ShippedTime'];
                            $single_order->markComplete();
                        } else {
                            $single_order->markError();
                        }
                    });
                } else {
                    $multiple_orders->map(function ($single_order) {
                        $single_order->markError();
                    });
                }
            }


            if ($processboxhelper->process($order)) {
                $response = $order->markShipped();
                // $response = ['success' => true, 'ShippedTime' => now()];
                if ($response['success']) {
                    $order->ShippedTime = $response['ShippedTime'];
                    $order->markComplete();
                } else {
                    $order->markError();
                }
            } else {
                $order->markError();
            }
        }
    }
}

My test is currently -

class ProcessOrderJobTest extends TestCase
{
    use RefreshDatabase;
    /** @test */
    public function job_processes_order_successfully()
    {
        $order = factory(ebayOrders::class)->create();

        $order = $this->createMock(ebayOrders::class);
        $order->method('markShipped')
            ->willReturn(['success' => true, 'ShippedTime' => now()]);

        $job = new ProcessOrderJob(1, 'user1');
        $job->handle();

        $this->assertCount(1, CompletedOrder::all());
        $this->assertDatabaseHas('completed_orders', $order->toArray());
    }
}