Below is sample script Script to retrieve Access and Refresh tokens using GlideOAuthClient libraries

This could be run from background scripts for testing purpose

Access token

var oAuthClient = new sn_auth.GlideOAuthClient();
var requestor_context = 'test';
var requestor_id = 'abc@xyz.com';
var oauth_profile_id = '43d6bab3db849f009a6ff9b61d961957'; // profile ID [sys_id of  'OAuth Entity Profiles' (oauth_entity_profile) record in OAUTH registry  record]

var params = {grant_type:"password", username:'admin', password:'pwd', oauth_requestor_context:requestor_context, oauth_requestor:requestor_id, oauth_provider_profile:oauth_profile_id}; //
var json = new global.JSON();
var text = json.encode(params);
var tokenResponse = oAuthClient.requestToken('oAuth Test', text); //'oAuth Test' is the name of the OAuth application registry record (oauth_entity)
var token = tokenResponse.getToken();
var access_token = token.getAccessToken() ;

gs.log("AccessToken:" + access_token);
gs.log("AccessTokenExpiresIn:" + token.getExpiresIn());
gs.log(" RefreshToken:" + token.getRefreshToken());


Refresh token

var oAuthClient = new sn_auth.GlideOAuthClient();
var requestor_context = 'test';
var requestor_id = 'abc@xyz.com';
var oauth_profile_id = '43d6bab3db849f009a6ff9b61d961957'; // profile ID [sys_id of  'OAuth Entity Profiles' (oauth_entity_profile) record in OAUTH registry  record]

var params = {grant_type:"refresh_token", refresh_token:"<value_of_refresh_token>", oauth_requestor_context:requestor_context, oauth_requestor:requestor_id, oauth_provider_profile:oauth_profile_id};
var json = new global.JSON();
var text = json.encode(params);
var tokenResponse = oAuthClient.requestToken('oAuth Test', text); //'oAuth Test' is the name of the OAuth application registry record (oauth_entity)
var token = tokenResponse.getToken();
var access_token = token.getAccessToken() ;

gs.log("AccessToken:" + access_token);
gs.log("AccessTokenExpiresIn:" + token.getExpiresIn());gs.log(" RefreshToken:" + token.getRefreshToken());

Making an outbound REST call with the retrieved token

// make the outbound REST call with the retrieved token