wn on cross-origin Worker construction must be SecurityErrors");
    t.done();
  }
}, "Cross-origin classic workers should fail to fetch");

async_test(function(t) {
  try {
    var w = new Worker("ftp://example.org/support/WorkerBasic.js", {type: "module"});
    w.onerror = t.step_func_done(function(e) {
      assert_true(e instanceof Event);
    });
  } catch (e) {
    assert_throws_dom("SecurityError", () => {throw e}, "DOMExceptions thrown on cross-origin module Worker construction must be SecurityError