title: add root elements in xml using XmlDocument C#
body: <p>I want to add a root elements --testsuites into my existing xml report.
  My current report looks like this </p>
  
  <pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
   &lt;testsuite name="classname" tests="9" failures="3" errors="6" time="2919" 
    disabled="0" skipped="0"&gt;
    &lt;testcase name="Setup1" time="5" classname="classname"&gt;
    &lt;/testcase&gt;
    &lt;testcase name="Setup2" time="49" classname="classname&gt;
    &lt;/testcase&gt;
    &lt;testcase name="Setup23" time="357" classname="classname"&gt;
    &lt;/testcase&gt;
    &lt;/testsuite&gt;
  </code></pre>
  
  <p>I want it change to </p>
  
  <pre><code>    &lt;?xml version="1.0" encoding="utf-8"?&gt;
      &lt;testsuites&gt;
       &lt;testsuite name="classname" tests="9" failures="3" errors="6" time="2919" disabled="0" skipped="0"&gt;
        &lt;testcase name="Setup1" time="5" classname="classname"&gt;
        &lt;/testcase&gt;
        &lt;testcase name="Setup2" time="49" classname="classname"&gt;
        &lt;/testcase&gt;
        &lt;testcase name="Setup23" time="357" classname="classname"&gt;
        &lt;/testcase&gt;
       &lt;/testsuite&gt;
      &lt;/testsuites&gt;
  </code></pre>
  
  <p>My current doesn't work on me</p>
  
  <pre><code>XmlDocument report = new XmlDocument();
  report.Load(fileOfReport);
  XmlElement root = report.CreateElement("root");
  root.SetAttribute("testsuites","testsuites");
  XmlElement child = report.CreateElement("child");
  child.GetElementsByTagName("testsuite");
  report.DocumentElement.AppendChild(root);
  root.AppendChild(child);        
  report.Save(fileOfReport);
  </code></pre>
  
  <p>Is there anyone can help?</p>