I'm creating some rostest files for camera1394, but most of them
require the presence of a real device. I don't want these tests run on
the Hudson build farm, because it lacks the requisite cameras.

I can define them using `rosbuild_add_rostest_labeled(device
tests/camera_hz.test)`, so they will run if $ROS_BUILD_TEST_LABEL is
set to `device`. But, they also run if ROS_BUILD_TEST_LABEL is unset.

Can I control how the test label is defined for Hudson builds?

Is there a different method recommended for managing these kinds of tests?
-- 
 joq