chromium/third_party/blink/web_tests/external/wpt/wasm/serialization/module/broadcastchannel-success.html

<!DOCTYPE html>
<!-- Based on similar tests in html/infrastructure/safe-passing-of-structured-data/shared-array-buffers/ -->
<meta charset="utf-8">
<title>Structured cloning of WebAssembly.Module: BroadcastChannel within the same agent cluster</title>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="./resources/test-incrementer.js"></script>

<div id="log"></div>

<script>
"use strict";

promise_test(t => {
  return createWasmModule().then(module => {
    let loadedIframes = 0;
    return Promise.all([
      createIFrame("resources/broadcastchannel-iframe.html"),
      createIFrame("resources/broadcastchannel-iframe.html"),
      createIFrame("resources/broadcastchannel-iframe.html")
    ]).then(() => {
      const thisIframe = loadedIframes++;
      const channel = new BroadcastChannel("channel name");

      return new Promise(resolve => {
        let soFar = 0;
        channel.onmessage = t.step_func(msg => {
          if (msg.module) {
            // We only care about "broadcasts" from the workers.
            return;
          }

          let {i, result} = msg.data;

          assert_in_array(i, [0, 1, 2], "Any message events must come from expected sources");
          assert_equals(result, i + 1, `iframe ${i} must return ${i+1}`);
          ++soFar;

          if (soFar === 3) {
            resolve();
          }
        });

        channel.postMessage({ module, i: thisIframe });
      });
    });
  });
});

function createIFrame(src) {
  return new Promise((resolve, reject) => {
    const iframe = document.createElement("iframe");
    iframe.src = src;
    iframe.onload = () => resolve(iframe);
    iframe.onerror = () => reject(`iframe with URL ${src} failed to load`);
    document.body.appendChild(iframe);
  });
}
</script>