NadaAldahleh/devise_oauth2_providable — comment on commit f88ce255d5cc6572bdebc161bd956ecb952825f4
File: spec/integration/oauth2_refresh_token_grant_type_strategy_spec.rb line 100
By wireframe:

client_secret is not required for the refresh_token grant type:
http://tools.ietf.org/html/draft-ietf-oauth-v2-23#section-6