public function emptyResponse(RunnerServiceContext $context, $responses)
    {
        if ($context instanceof QtiRunnerServiceContext) {
            $similar = 0;

            /** @var ResponseVariable $responseVariable */
            foreach ($responses as $responseVariable) {
                $value = $responseVariable->getValue();
                $default = $responseVariable->getDefaultValue();

                // Similar to default ?
                if (TestRunnerUtils::isQtiValueNull($value) === true) {
                    if (TestRunnerUtils::isQtiValueNull($default) === true) {
                        $similar++;
                    }
                } elseif ($value->equals($default) === true) {
                    $similar++;
                }
            }

            $respCount = count($responses);
            return $respCount > 0 && $similar == $respCount;
        } else {
            throw new \common_exception_InvalidArgumentType(
                'QtiRunnerService',
                'storeItemResponse',
                0,
                'oat\taoQtiTest\models\runner\QtiRunnerServiceContext',
                $context
            );
        }
    }