diff --git a/tests/Unit/Service/MailServiceTest.php b/tests/Unit/Service/MailServiceTest.php
index 464ec7360a..9c9d59eb4f 100644
--- a/tests/Unit/Service/MailServiceTest.php
+++ b/tests/Unit/Service/MailServiceTest.php
@@ -109,7 +109,7 @@ public function testFailToSendMailToUnsignedUser():void {
 			});
 		$this->appConfig
 			->method('getValueBool')
-			->will($this->returnValue('1'));
+			->will($this->returnValue(true));
 		$actual = $this->service->notifyUnsignedUser($signRequest, 'a@b.coop');
 		$this->assertNull($actual);
 	}