diff --git a/tests/codeigniter/helpers/email_helper_test.php b/tests/codeigniter/helpers/email_helper_test.php
index 53a2068..529e969 100644
--- a/tests/codeigniter/helpers/email_helper_test.php
+++ b/tests/codeigniter/helpers/email_helper_test.php
@@ -13,6 +13,7 @@
 		$this->assertEquals(FALSE, valid_email('test@test@test.com'));
 		$this->assertEquals(TRUE, valid_email('test@test.com'));
 		$this->assertEquals(TRUE, valid_email('my.test@test.com'));
+		$this->assertEquals(TRUE, valid_email('my.test@subdomain.test.com'));
 	}
 
 	public function test_send_mail()