title: nightwatch waitForElementVisible and assert.visible not working
body: <p>am new to nightwatch</p>
  
  <p>I just  copy the first code form <a href="http://nightwatchjs.org/" rel="nofollow noreferrer">http://nightwatchjs.org/</a> 
  Below showing the code</p>
  
  <p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
  <div class="snippet-code">
  <pre class="snippet-code-html lang-html prettyprint-override"><code>module.exports = {
    'Demo test Google' : function (client) {
      client
        .url('http://www.google.com')
        .waitForElementVisible('body', 1000)
        .assert.title('Google')
        .assert.visible('input[type=text]')
        .setValue('input[type=text]', 'rembrandt van rijn')
        .waitForElementVisible('button[name=btnG]', 1000)
        .click('button[name=btnG]')
        .pause(1000)
        .assert.containsText('ol#rso li:first-child',
          'Rembrandt - Wikipedia')
        .end();
    }
  };</code></pre>
  </div>
  </div>
  </p>
  
  <p>And getting Failure</p>
  
  <p><a href="https://i.stack.imgur.com/sLVYD.jpg" rel="nofollow noreferrer">error result</a></p>
  
  <p>.waitForElementVisible('body', 20000) is showing error and also .assert.visible('input[type=text]') is getting fail</p>