ant/src/etc/testcases/taskdefs/conditions/isreference.xml

<project default="nope">
  <path id="global-path-id"/>
  <echo id="echo-id"/>

  <target name="nope">
    <fail>This build file should be run by a testcase</fail>
  </target>

  <target name="define">
    <path id="target-path-id"/>
  </target>

  <target name="basic" depends="define">
    <condition property="global-path">
      <isreference refid="global-path-id"/>
    </condition>
    <condition property="target-path">
      <isreference refid="target-path-id"/>
    </condition>
  </target>

  <target name="isreference-incomplete">
    <condition property="foo">
      <isreference/>
    </condition>
  </target>

  <target name="type">
    <condition property="global-path">
      <isreference refid="global-path-id" type="path"/>
    </condition>
    <condition property="global-path-as-fileset">
      <isreference refid="global-path-id" type="fileset"/>
    </condition>
    <condition property="global-path-as-foo">
      <isreference refid="global-path-id" type="foo"/>
    </condition>
    <condition property="global-echo">
      <isreference refid="echo-id" type="echo"/>
    </condition>
  </target>

</project>