LayoutTests/http/tests/cache/disable-resource-caching-preserves-request-cache-control.html

<!DOCTYPE html>
<html>
<body>
<div id="console"></div>
<script>
if (window.testRunner) {
    testRunner.dumpAsText();
    testRunner.waitUntilDone();
}

function log(message)
{
    const line = document.createElement("div");
    line.textContent = message;
    document.getElementById("console").appendChild(line);
}

async function cacheControlSentToServer(options)
{
    const response = await fetch("/xmlhttprequest/resources/print-cache-control-header.cgi?" + Math.random(), options);
    const text = (await response.text()).trim();
    return text ? text.replace(/^HTTP_CACHE_CONTROL:\s*/, "") : "(none)";
}

async function run()
{
    try {
        log("caching enabled, page sets max-age=12345: " + await cacheControlSentToServer({ headers: { "cache-control": "max-age=12345" } }));

        if (window.internals)
            internals.setResourceCachingDisabledByWebInspector(true);

        log("caching disabled, no page header: " + await cacheControlSentToServer({ }));
        log("caching disabled, page sets max-age=12345: " + await cacheControlSentToServer({ headers: { "cache-control": "max-age=12345" } }));

        if (window.internals)
            internals.setResourceCachingDisabledByWebInspector(false);
    } catch (exception) {
        log("threw " + exception);
    }

    if (window.testRunner)
        testRunner.notifyDone();
}

run();
</script>
</body>
</html>