build.xml

<project name="TestNG_WORKSPACE" default="junit-report" basedir=".">
  <!-- Sets the property variables to point to respective directories -->
  <property name="junit-xml-dir" value="./"/>
  <property name="report-dir" value="${basedir}/report" />
  
  <!-- Ant target to generate html report -->
  <target name="junit-report">
    <!-- Delete and recreate the html report directories -->
    <delete dir="${report-dir}" failonerror="false"/>
    <mkdir dir="${report-dir}" />
    <!-- Ant task to generate the html report.
    todir - Directory to generate the output reports

    fileset - Directory to look for the junit xml reports.

    report - defines the type of format to be generated.
      Here we are using "noframes" which generates a single html report.
     -->
    <junitreport todir="${report-dir}/">
      <fileset dir="${junit-xml-dir}">
        <include name="**/result*.xml" />
      </fileset>
      <report format="noframes" todir="${report-dir}/" styledir="."/>
    </junitreport>
  </target>
</project>