diff --git a/tests/GuardTest.php b/tests/GuardTest.php
index 701ceb5..bd410c6 100644
--- a/tests/GuardTest.php
+++ b/tests/GuardTest.php
@@ -289,7 +289,8 @@ public function testTokenIsRemovedFromStorageWhenPersistentModeIsOff()
         $requestHandlerProphecy = $this->prophesize(RequestHandlerInterface::class);
         $requestHandlerProphecy
             ->handle(Argument::type(ServerRequestInterface::class))
-            ->willReturn($responseProphecy->reveal());
+            ->willReturn($responseProphecy->reveal())
+            ->shouldBeCalledOnce();
 
         $responseFactoryProphecy = $this->prophesize(ResponseFactoryInterface::class);