Show trace in selenium tests

gistfile1.aw

<?php

protected function onNotSuccessfulTest(\Exception $e)
    {
        try {
            return parent::onNotSuccessfulTest($e);
        } catch (\Exception $newException) {
            if ($e instanceof \PHPUnit_Framework_ExpectationFailedException && false == $e->getComparisonFailure()) {
                throw $e;
            }

            throw $newException;
        }
    }