A good litmus test may be the site's name.

Germany provides a good litmus test, given its large economy and rapid shift to renewable energy in the past five years.

And lastly, the stimulus package is probably too small by a factor of about three, a good litmus is state and local governments.

Morgan O'Driscoll 's Irish and international art this week was a good litmus test for the online auction market in the current health crisis.