Since the below call to `compare_dft_vs_photon_config` takes a while to run, I would recommend rewording this to something like `"Starting tests using config file with N_PHOTONS = "+str(np)`.  Also, it would be nice to have some kind of progress report as the tests are running so the user knows that the computer didn't freeze.  e.g. Maybe every iteration, do `print '.',`.  Similar comments apply to the object tests above.