plugins/DeviceDetectorCache/config/test.php

<?php

use Piwik\Plugins\DeviceDetectorCache\CachedEntry;

return [
    'DeviceDetectorCacheIgnoreUserAgentsWithLessThanXRequests' => 0,
    \Piwik\DeviceDetector\DeviceDetectorFactory::class => Piwik\DI::decorate(function ($previous) {
        CachedEntry::setCacheDir(PIWIK_DOCUMENT_ROOT . '/tmp/devicecachetests/');

        return $previous;
    })
];