LayoutTests/fetch/header-constructor-overriden.html

<!DOCTYPE HTML>
<html>
<head>
<script src="../resources/js-test-pre.js"></script>
</head>
<body>
<iframe></iframe>
<script>
description("This test should create a Headers, override the Headers property and try creating new Headers from it.");

let array = [ [ 'hello', 'world' ] ];
var headers = new Headers(array);
shouldBeEqualToString("headers.get('hello')", "world");

var OldHeaders = Headers;

headers.constructor = null;
Headers = {};
window.Headers = {};

var newHeaders = new OldHeaders(headers);
shouldBeEqualToString("newHeaders.get('hello')", "world");

var response = new Response("", {headers: headers});
shouldBeEqualToString("response.headers.get('hello')", "world");

</script>
<script src="../resources/js-test-post.js"></script>
</body>
</html>