anchor.diff:           ]].
   
   oauth_for_test() ->
  -    [?assertEqual(oauth_for(provider, Account, Providers), Expected)
  +    [?assertEqual(Expected, oauth_for(email, Account, Providers))
        || {Account, Providers, Expected}
               <- [
                   {<<"account@gmail.com">>, [{google, prov}], {ok, prov}},
  
positive.code: -spec oauth_for(provider | email, binary(), [proplists:property()]) ->
      {ok, {ClientID :: string, ClientSecret :: string}} | {error, _}.
  oauth_for(provider, Provider, Providers) ->
      case proplists:get_value(Provider, Providers) of
        undefined ->
          {error, {no_provider_oauth, Provider}}; 
  
negative.code:                ]].
  
  to_query_string_test() ->
    [?assertEqual(Expected, to_query_string(Props))
     || {Props, Expected}
        <- [
            { [{a, <<"1234">>}], <<"a=1234&">> },
  