gistfile1.js

browser
  .chain
  .session()
  .and(function (browser) { // log out
    try {
      browser
        .open('/')
        .assertElementPresent('link=Log out')
        .clickAndWait('link=Log out')
        .assertElementPresent('link=Log in')
        .testComplete();
    } catch (err) {
      if (err.message.match(/^assertElementPresent\(link=Log out/)) {
        console.log(stylize('  No log out necessary', 'grey'));
      } else {
        throw err;
      }
    }
  })
  .assertTitle('whatever')
  .testComplete()
  .end(function (err) {
    if (err) {
      console.log('ERROR');
      throw err;
    }
    console.log('done');
  });