cakephp/tests/test_app/TestApp/Error/TestAppsExceptionRenderer.php

<?php

namespace TestApp\Error;

use Cake\Controller\Controller;
use Cake\Error\ExceptionRenderer;
use Cake\Http\Response;
use Cake\Http\ServerRequest;
use Cake\Routing\Router;
use Psr\Http\Message\ServerRequestInterface;
use TestApp\Controller\TestAppsErrorController;

class TestAppsExceptionRenderer extends ExceptionRenderer
{

    /**
     * {@inheritDoc}
     */
    protected function _getController(ServerRequestInterface $request = null)
    {
        if(!$request) {
            if (!$request = Router::getRequest(true)) {
                $request = new ServerRequest();
            }
        }
        $response = new Response();
        try {
            $controller = new TestAppsErrorController($request, $response);
            $controller->viewBuilder()->layout('banana');
        } catch (\Exception $e) {
            $controller = new Controller($request, $response);
            $controller->viewBuilder()->templatePath('Error');
        }

        return $controller;
    }
}