diff --git a/tests/Panel/FieldTest.php b/tests/Panel/FieldTest.php
index eb9de1e682..5f532a3ac0 100644
--- a/tests/Panel/FieldTest.php
+++ b/tests/Panel/FieldTest.php
@@ -313,6 +313,7 @@ public function testSlug(): void
 		$expected = [
 			'label' => 'URL appendix',
 			'type'  => 'slug',
+			'allow' => 'a-z0-9'
 		];
 
 		$this->assertSame($expected, $field);