add_task(async function test() {
  await BrowserTestUtils.withNewTab({ gBrowser, url: "about:blank" }, async function(newBrowser) {
    await ContentTask.spawn(newBrowser, null, async function() {
      var prin = content.document.nodePrincipal;
      Assert.notEqual(prin, null, "Loaded principal must not be null");
      Assert.notEqual(prin, undefined, "Loaded principal must not be undefined");

      const secMan = Cc["@mozilla.org/scriptsecuritymanager;1"]
                       .getService(Ci.nsIScriptSecurityManager);
      Assert.equal(secMan.isSystemPrincipal(prin), false,
        "Loaded principal must not be system");
    });
  });
});