Improved error message when the user hasn't installed any testing adapters.
Improved error message when the user hasn't installed any testing adapters.

ntotomanov-taulia/geb,kgeis/geb,onBass-naga/geb,kgeis/geb,pierre-hilt/geb,madmas/geb,kgeis/geb,geb/geb,geb/geb,menonvarun/geb,ntotomanov-taulia/geb,madmas/geb,menonvarun/geb,madmas/geb,pierre-hilt/geb,menonvarun/geb,onBass-naga/geb,pierre-hilt/geb