diff --git a/src/Dao/AbstractDao.php b/src/Dao/AbstractDao.php
index 4a7ae452..f863b1e3 100644
--- a/src/Dao/AbstractDao.php
+++ b/src/Dao/AbstractDao.php
@@ -22,12 +22,6 @@ abstract class AbstractDao implements ICrudDao
 			});
 	}
 
-	public function setDatabaseConnection(\Szurubooru\DatabaseConnection $databaseConnection)
-	{
-		$this->pdo = $databaseConnection->getPDO();
-		$this->fpdo = new \FluentPDO($this->pdo);
-	}
-
 	public function getTableName()
 	{
 		return $this->tableName;
@@ -189,6 +183,12 @@ abstract class AbstractDao implements ICrudDao
 		return $entities;
 	}
 
+	private function setDatabaseConnection(\Szurubooru\DatabaseConnection $databaseConnection)
+	{
+		$this->pdo = $databaseConnection->getPDO();
+		$this->fpdo = new \FluentPDO($this->pdo);
+	}
+
 	private function decorateQueryFromFilter($query, \Szurubooru\SearchServices\Filters\IFilter $filter)
 	{
 		foreach ($filter->getRequirements() as $requirement)
diff --git a/src/Injector.php b/src/Injector.php
index 4f8b665f..d8a56e77 100644
--- a/src/Injector.php
+++ b/src/Injector.php
@@ -22,6 +22,11 @@ final class Injector
 	{
 		return self::$container->get($className);
 	}
+
+	public static function set($className, $object)
+	{
+		return self::$container->set($className, $object);
+	}
 }
 
 Injector::init();
diff --git a/src/Upgrades/Upgrade04.php b/src/Upgrades/Upgrade04.php
index 1e76f5ed..ca879ea6 100644
--- a/src/Upgrades/Upgrade04.php
+++ b/src/Upgrades/Upgrade04.php
@@ -19,8 +19,6 @@ class Upgrade04 implements IUpgrade
 
 	public function run(\Szurubooru\DatabaseConnection $databaseConnection)
 	{
-		$this->postDao->setDatabaseConnection($databaseConnection);
-
 		$databaseConnection->getPDO()->exec('ALTER TABLE "posts" ADD COLUMN contentMimeType TEXT DEFAULT NULL');
 
 		$posts = $this->postDao->findAll();
@@ -28,7 +26,7 @@ class Upgrade04 implements IUpgrade
 		{
 			if ($post->getContentType() !== \Szurubooru\Entities\Post::POST_TYPE_YOUTUBE)
 			{
-				$fullPath = $this->fileService->getFullPath($this->postService->getPostContentPath($post));
+				$fullPath = $this->fileService->getFullPath($post->getContentPath());
 				$mime = \Szurubooru\Helpers\MimeHelper::getMimeTypeFromFile($fullPath);
 				$post->setContentMimeType($mime);
 				$this->postDao->save($post);
diff --git a/tests/AbstractDatabaseTestCase.php b/tests/AbstractDatabaseTestCase.php
index 2fead051..42fa02f2 100644
--- a/tests/AbstractDatabaseTestCase.php
+++ b/tests/AbstractDatabaseTestCase.php
@@ -12,6 +12,7 @@ abstract class AbstractDatabaseTestCase extends \Szurubooru\Tests\AbstractTestCa
 		$config->set('database/dsn', 'sqlite::memory:');
 
 		$this->databaseConnection = new \Szurubooru\DatabaseConnection($config);
+		\Szurubooru\Injector::set(\Szurubooru\DatabaseConnection::class, $this->databaseConnection);
 
 		$upgradeRepository = \Szurubooru\Injector::get(\Szurubooru\Upgrades\UpgradeRepository::class);
 		$upgradeService = new \Szurubooru\Services\UpgradeService($config, $this->databaseConnection, $upgradeRepository);
diff --git a/tests/AbstractTestCase.php b/tests/AbstractTestCase.php
index 64b8699e..e78f38d4 100644
--- a/tests/AbstractTestCase.php
+++ b/tests/AbstractTestCase.php
@@ -36,6 +36,11 @@ abstract class AbstractTestCase extends \PHPUnit_Framework_TestCase
 		return __DIR__ . DIRECTORY_SEPARATOR . 'test_files' . DIRECTORY_SEPARATOR . $fileName;
 	}
 
+	protected function setUp()
+	{
+		\Szurubooru\Injector::init();
+	}
+
 	protected function tearDown()
 	{
 		$this->cleanTestDirectory();