src/etc/testcases/taskdefs/tar.xml

<?xml version="1.0"?>

<project name="xxx-test" basedir="." default="test1">

  <target name="test1">
    <tar/>
  </target>

  <target name="test2">
    <tar tarfile=""/>
  </target>

  <target name="test3">
    <tar basedir=""/>
  </target>

</project>