如何设置Ant'junit'任务的工作目录？

 <property name="src.dir" value="src"/>
 <property name="build.dir" value="build"/>
 <property name="test.dir" value="test"/>
 <property name="test.classes.dir" value="${build.dir}/test/classes"/>
 <property name="test.reports.dir" value="${build.dir}/test/reports"/>

 <target name="init">
    <tstamp/>
    <mkdir dir="${build.dir}"/>
    <mkdir dir="${test.classes.dir}"/>
    <mkdir dir="${test.reports.dir}"/>
  </target>

 <target name="compile" depends="init">
    <javac srcdir="${src.dir}" destdir="${build.dir}">
     <classpath refid="master-classpath"/>
    </javac>
  </target>

 <target name="test-compile" depends="compile">
    <javac srcdir="${test.dir}" destdir="${test.classes.dir}">
     <classpath refid="master-classpath"/>
     <classpath location="${build.dir}"/>
    </javac>
  </target>

 <target name="test" depends="test-compile">
   <junit dir="${test.classes.dir}" fork="yes">
     <classpath refid="master-classpath"/>
     <classpath location="${build.dir}"/>
      <formatter type="xml"/>
     <batchtest todir="${test.reports.dir}">
       <fileset dir="${test.classes.dir}">
         <include name="**/*Test*.class"/>
        </fileset>
      </batchtest>
    </junit>
  </target>

 <target name="clean">
   <delete dir="${build.dir}"/>
  </target>
</project>