Return annotated @runInSeparateProcess

tests/logger/FileLoggerTest.php

@@ -48,6 +48,9 @@ class FileLoggerTest extends PHPUnit_Framework_TestCase
         $this->assertInstanceOf('FileLogger', $logger);
     }
 
+    /**
+     * @runInSeparateProcess
+     */
     public function testCannotWrite()
     {
         if (!defined('DEBUG')) {