test_ext_browserSettings.js

add_task(async function test_exceptions() {
  async function background() {
    await browser.test.assertRejects(
      browser.browserSettings.contextMenuShowEvent.set({value: "bad"}),
      /bad is not a valid value for contextMenuShowEvent/,
      "contextMenuShowEvent.set rejects with an invalid value.");

    browser.test.sendMessage("done");
  }

  let extension = ExtensionTestUtils.loadExtension({
    background,
    manifest: {
      permissions: ["browserSettings"],
    },
    useAddonManager: "temporary",
  });

  await promiseStartupManager();
  await extension.startup();
  await extension.awaitMessage("done");
  await extension.unload();

  await promiseShutdownManager();
});