diff --git a/src/Symfony/Component/EventDispatcher/Tests/ImmutableEventDispatcherTest.php b/src/Symfony/Component/EventDispatcher/Tests/ImmutableEventDispatcherTest.php
index edce6f199d..1a33c19b15 100644
--- a/src/Symfony/Component/EventDispatcher/Tests/ImmutableEventDispatcherTest.php
+++ b/src/Symfony/Component/EventDispatcher/Tests/ImmutableEventDispatcherTest.php
@@ -47,7 +47,7 @@ class ImmutableEventDispatcherTest extends TestCase
             ->with($event, 'event')
             ->willReturn($resultEvent);
 
-        $this->assertSame($resultEvent, $this->dispatcher->dispatch('event', $event));
+        $this->assertSame($resultEvent, $this->dispatcher->dispatch($event, 'event'));
     }
 
     public function testGetListenersDelegates()