fix test failed messages (diff non-zero return value means either diff failed or there was a difference between the inputs)
fix test failed messages (diff non-zero return value means either diff failed or there was a difference between the inputs)

alexsaveliev/srclib-ruby,alexsaveliev/srclib-ruby,alexsaveliev/srclib-ruby,alexsaveliev/srclib-ruby,alexsaveliev/srclib-ruby,alexsaveliev/srclib-ruby