Changed references to functional tests by database tests

module/Common/test-db/DbUnit/DatabaseTestCase.php

@@ -0,0 +1,33 @@
+<?php
+declare(strict_types=1);
+
+namespace ShlinkioTest\Shlink\Common\DbUnit;
+
+use Doctrine\ORM\EntityManagerInterface;
+use PHPUnit\Framework\TestCase;
+
+abstract class DatabaseTestCase extends TestCase
+{
+    protected const ENTITIES_TO_EMPTY = [];
+
+    /** @var EntityManagerInterface */
+    public static $em;
+
+    protected function getEntityManager(): EntityManagerInterface
+    {
+        return static::$em;
+    }
+
+    public function tearDown()
+    {
+        // Empty all entity tables defined by this test after each test
+        foreach (static::ENTITIES_TO_EMPTY as $entityClass) {
+            $qb = $this->getEntityManager()->createQueryBuilder();
+            $qb->delete($entityClass, 'x');
+            $qb->getQuery()->execute();
+        }
+
+        // Clear entity manager
+        $this->getEntityManager()->clear();
+    }
+}