<launch>
  <node name="talker" pkg="rospy" type="talker.py" />
  <group ns="foo">
    <node name="talker" pkg="rospy" type="talker.py" />
  </group>
  <group ns="bar">
    <node name="talker" pkg="rospy" type="talker.py" />
  </group>
  <test test-name="rostopic_unit" pkg="rostopic" type="test_rostopic.py" />
</launch>
