mozilla-release/testing/web-platform/tests/web-share/share-sharePromise-internal-slot.https.html

<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8" />
    <link rel="help" href="https://github.com/w3c/web-share/pull/113" />
    <title>WebShare Test: only one share at a time</title>
    <script src="/resources/testharness.js"></script>
    <script src="/resources/testharnessreport.js"></script>
    <script src="/resources/testdriver.js"></script>
    <script src="/resources/testdriver-vendor.js"></script>
  </head>
  <body>
    <button>
    <script>
      setup({ allow_uncaught_exception:true });
      promise_test(async t => {
        const button = document.querySelector("button");
        const p = new Promise(r => {
          button.onclick = () => {
            const promises = [];
            promises.push(
              navigator.share({ title: "should be pending" }),
              navigator.share({ title: "should reject" }),
              navigator.share({ title: "should also reject" })
            );
            r(promises);
          };
        });
        test_driver.click(button);
        const [, promise2, promise3] = await p;
        await Promise.all([
          promise_rejects_dom(t, "InvalidStateError", promise2),
          promise_rejects_dom(t, "InvalidStateError", promise3)
        ]);
      }, "Only allow one share call at a time, which is controlled by the [[sharePromise]] internal slot.");
    </script>
  </body>
</html>