diff --git a/tests/Formatter/EGFormatterTest.php b/tests/Formatter/EGFormatterTest.php
index bef7002..8fdb4ce 100644
--- a/tests/Formatter/EGFormatterTest.php
+++ b/tests/Formatter/EGFormatterTest.php
@@ -35,6 +35,8 @@ public function providerFormat() : array
             ['1234', null],
             ['12345', '12345'],
             ['123456', null],
+            ['1234567', '1234567'],
+            ['12345678', null],
 
             ['A', null],
             ['AB', null],