ant/src/etc/testcases/taskdefs/xmlns.xml

<?xml version="1.0"?>
<project name="test">

  <property name="testcases.dir" location="../../../../build/testcases"/>

  <path id="testclasses">
    <pathelement location="${testcases.dir}" />
    <pathelement path="${java.class.path}" />
  </path>

  <target name="xmlns" xmlns:test="this.is.another.test.uri">
    <typedef classname="org.apache.tools.ant.taskdefs.XmlnsTest$MyTask"
             classpathref="testclasses"
             name="mytask"
             uri="this.is.another.test.uri" />
    <test:mytask/>
  </target>

  <target name="xmlns.file" xmlns:test="this.is.a.test.uri">
    <typedef file="test.antlib.xml"
             classpathref="testclasses"
             uri="this.is.a.test.uri" />
    <test:mytask/>
  </target>

  <target name="core">
    <typedef file="test.antlib.xml"
             classpathref="testclasses"
             uri="antlib:org.apache.tools.ant" />
    <mytask/>
  </target>

  <target name="excluded">
    <typedef file="test.antlib.xml"
             classpathref="testclasses"
             uri="ant:notallowed" />
  </target>


</project>