diff --git a/test/PHPMailerTest.php b/test/PHPMailerTest.php
index 92914d7ee..f5cd0e906 100644
--- a/test/PHPMailerTest.php
+++ b/test/PHPMailerTest.php
@@ -1493,7 +1493,7 @@ public function testAltBodyAttachment()
         }
 
         //Test using non-existent UNC path
-        self::assertFalse($this->Mail->addAttachment('\\\\nowhere\nothing'));
+        self::assertFalse($this->Mail->addAttachment('\\\\nowhere\\nothing'));
 
         $this->buildBody();
         self::assertTrue($this->Mail->send(), $this->Mail->ErrorInfo);