gistfile1.php

<?php

    namespace Saito\Test;

    use Cake\Error\ExceptionRenderer as CakeExceptionRenderer;

    class ExceptionRenderer extends CakeExceptionRenderer {

        public function __construct(\Exception $exception)
        {
            throw $exception;
        }

    }

php

<?php
…

	public function setUp() {
		parent::setUp();
            	Configure::write(
                	'Error.exceptionRenderer',
                	'\Saito\Test\ExceptionRenderer'

            	);
        }