diff --git a/src/Migration/MigrationManager.php b/src/Migration/MigrationManager.php
index <HASH>..<HASH> 100644
--- a/src/Migration/MigrationManager.php
+++ b/src/Migration/MigrationManager.php
@@ -38,7 +38,7 @@ class MigrationManager
     /**
      * @var string[]
      */
-    private $knownVersions;
+    private $knownVersions = array();
 
     /**
      * Creates a new migration manager.
diff --git a/tests/Migration/MigrationManagerTest.php b/tests/Migration/MigrationManagerTest.php
index <HASH>..<HASH> 100644
--- a/tests/Migration/MigrationManagerTest.php
+++ b/tests/Migration/MigrationManagerTest.php
@@ -282,6 +282,13 @@ class MigrationManagerTest extends PHPUnit_Framework_TestCase
         $this->assertSame(array('0.8', '0.10', '1.0', '2.0'), $this->manager->getKnownVersions());
     }
 
+    public function testGetKnownVersionsWithoutMigrations()
+    {
+        $this->manager = new MigrationManager(array());
+
+        $this->assertSame(array(), $this->manager->getKnownVersions());
+    }
+
     /**
      * @param string $sourceVersion
      * @param string $targetVersion
Fixed bug when no migrations are passed