diff --git a/tests/file_loader_test.php b/tests/file_loader_test.php
index 7269a2f..83033de 100644
--- a/tests/file_loader_test.php
+++ b/tests/file_loader_test.php
@@ -8,29 +8,62 @@
  *
  */
 
+use Phpbb\Epv\Files\FileLoader;
+use Phpbb\Epv\Files\Type\LangFile;
+use Phpbb\Epv\Files\Type\MigrationFile;
+use Phpbb\Epv\Files\Type\PHPFile;
+use Phpbb\Epv\Files\Type\PHPFileInterface;
+use Phpbb\Epv\Files\Type\YmlFile;
+use Phpbb\Epv\Tests\Mock\Output;
+
 class file_loader_test extends PHPUnit_Framework_TestCase {
+
+	/** @var FileLoader */
+	private static $loader;
+
 	public static function setUpBeforeClass()
 	{
 		require_once('./tests/Mock/Output.php');
+
+		static::$loader = new FileLoader(new Output(), false, 'tests/testFiles/', '.');
 	}
 
-	private function getLoader()
+	public function test_file_php() {
+
+		$type = static::$loader->loadFile('tests/testFiles/test.txt.php');
+		$typePhp = static::$loader->loadFile('tests/testFiles/test.php');
+		$typeMigration = static::$loader->loadFile('tests/testFiles/migrations/test.php');
+
+		$this->assertTrue($type instanceof PHPFile);
+		$this->assertTrue($typePhp instanceof PHPFile);
+		$this->assertFalse($typePhp instanceof MigrationFile);
+		$this->assertFalse($typePhp instanceof LangFile);
+		$this->assertTrue($typeMigration instanceof PHPFileInterface); // It extends from the interface!
+		$this->assertTrue($typeMigration instanceof MigrationFile, 'type is migration file');
+	}
+
+	public function test_file_yml()
 	{
-		return $file = new \Phpbb\Epv\Files\FileLoader(new \Phpbb\Epv\Tests\Mock\Output(), false, 'tests/testFiles/', '.');
+		$validYml = static::$loader->loadFile('tests/testFiles/valid.yml');
+		$invalidImportYml = static::$loader->loadFile('tests/testFiles/invalid_import.yml');
+		$emptyImportYml = static::$loader->loadFile('tests/testFiles/empty_import.yml');
+
+		$this->assertTrue($validYml instanceof YmlFile);
+		$this->assertTrue($invalidImportYml instanceof YmlFile);
+		$this->assertTrue($emptyImportYml instanceof YmlFile);
 	}
 
-	public function test_file_php() {
-		$file = $this->getLoader();
-
-		$type = $file->loadFile('tests/testFiles/test.txt.php');
-		$typePhp = $file->loadFile('tests/testFiles/test.php');
-		$typeMigration = $file->loadFile('tests/testFiles/migrations/test.php');
-
-		$this->assertTrue($type instanceof \Phpbb\Epv\Files\Type\PHPFile);
-		$this->assertTrue($typePhp instanceof \Phpbb\Epv\Files\Type\PHPFile);
-		$this->assertFalse($typePhp instanceof \Phpbb\Epv\Files\Type\MigrationFile);
-		$this->assertFalse($typePhp instanceof \Phpbb\Epv\Files\Type\LangFile);
-		$this->assertTrue($typeMigration instanceof \Phpbb\Epv\Files\Type\PHPFileInterface); // It extends from the interface!
-		$this->assertTrue($typeMigration instanceof \Phpbb\Epv\Files\Type\MigrationFile, 'type is migration file');
+	public function test_file_invalid_yml()
+	{
+		$this->setExpectedException(Exception::class);
+		$invalidYml = static::$loader->loadFile('tests/testFiles/invalid.yml');
+		$this->assertNull($invalidYml);
+	}
+
+	public function test_file_empty_yml()
+	{
+		$this->setExpectedException(Exception::class);
+		$emptyYml = static::$loader->loadFile('tests/testFiles/empty.yml');
+		$this->assertNull($emptyYml);
 	}
 }
diff --git a/tests/testFiles/empty.yml b/tests/testFiles/empty.yml
new file mode 100644
index 0000000..e69de29
diff --git a/tests/testFiles/empty_import.yml b/tests/testFiles/empty_import.yml
new file mode 100644
index 0000000..275232c
--- /dev/null
+++ b/tests/testFiles/empty_import.yml
@@ -0,0 +1,6 @@
+imports:
+    - { resource: empty.yml }
+
+services:
+    some.service.name:
+        class: a\b\c
diff --git a/tests/testFiles/invalid.yml b/tests/testFiles/invalid.yml
new file mode 100644
index 0000000..a2f2665
--- /dev/null
+++ b/tests/testFiles/invalid.yml
@@ -0,0 +1,2 @@
+services:
+	some.
diff --git a/tests/testFiles/invalid_import.yml b/tests/testFiles/invalid_import.yml
new file mode 100644
index 0000000..c171877
--- /dev/null
+++ b/tests/testFiles/invalid_import.yml
@@ -0,0 +1,6 @@
+imports:
+    - { resource: invalid.yml }
+
+services:
+    some.service.name:
+        class: a\b\c
diff --git a/tests/testFiles/valid.yml b/tests/testFiles/valid.yml
new file mode 100644
index 0000000..36c176a
--- /dev/null
+++ b/tests/testFiles/valid.yml
@@ -0,0 +1,3 @@
+services:
+    some.service.name:
+        class: a\b\c