title: check for strings that are at least 1 character long
body: <p>I often see <a href="http://php.net/manual/en/function.strlen.php" rel="nofollow">strlen</a> used. Are these 2 tests equivalent for all values of <code>$str</code>?</p>
  
  <p><code>is_string($str) &amp;&amp; 0 !== strlen($str)</code></p>
  
  <p><code>is_string($str) &amp;&amp; '' !== $str</code></p>