fix for failing test

Signed-off-by: bidi47 <bidi@apidemia.com>

Author: bidi47

test/Unit/Page/Handler/PageHandlerTest.php

@@ -56,6 +56,10 @@ public function testHandle(): void
             ->method('getAttribute')
             ->willReturn($routeResult);
 
+        $request
+            ->method('getHeaderLine')
+            ->willReturn('');
+
         $template
             ->method('render')
             ->willReturn('<p>' . $routeName . '</p>');