src/third_party/web_platform_tests/XMLHttpRequest/setrequestheader-case-insensitive.htm - cobalt - Git at Google

 <!doctype html>
 <html>
   <head>
     <title>XMLHttpRequest: setRequestHeader() - headers that differ in case</title>
     <script src="/resources/testharness.js"></script>
     <script src="/resources/testharnessreport.js"></script>
     <link rel="help" href="https://xhr.spec.whatwg.org/#the-setrequestheader()-method" data-tested-assertations="/following::ol/li[6] /following::ol/li[7]" />
   </head>
   <body>
     <div id="log"></div>
     <script>
       test(function() {
         var client = new XMLHttpRequest()
         client.open("POST", "resources/inspect-headers.py?filter_value=t1, t2, t3", false)
         client.setRequestHeader("x-test", "t1")
         client.setRequestHeader("X-TEST", "t2")
         client.setRequestHeader("X-teST", "t3")
         client.send(null)
         assert_equals(client.responseText, "x-test,")
       })
     </script>
   </body>
 </html>
	<!doctype html>
	<html>
	<head>
	<title>XMLHttpRequest: setRequestHeader() - headers that differ in case</title>
	<script src="/resources/testharness.js"></script>
	<script src="/resources/testharnessreport.js"></script>
	<link rel="help" href="https://xhr.spec.whatwg.org/#the-setrequestheader()-method" data-tested-assertations="/following::ol/li[6] /following::ol/li[7]" />
	</head>
	<body>
	<div id="log"></div>
	<script>
	test(function() {
	var client = new XMLHttpRequest()
	client.open("POST", "resources/inspect-headers.py?filter_value=t1, t2, t3", false)
	client.setRequestHeader("x-test", "t1")
	client.setRequestHeader("X-TEST", "t2")
	client.setRequestHeader("X-teST", "t3")
	client.send(null)
	assert_equals(client.responseText, "x-test,")
	})
	</script>
	</body>
	</html>