Add unit tests for new classes

Signed-off-by: Julius Härtl <jus@bitgrid.net>

tests/unit/Db/CardTest.php

@@ -25,8 +25,9 @@ namespace OCA\Deck\Db;
 
 use DateInterval;
 use DateTime;
+use Test\TestCase;
 
-class CardTest extends \PHPUnit_Framework_TestCase {
+class CardTest extends TestCase {
 	private function createCard() {
 		$card = new Card();
 		$card->setId(1);