function jwtDecode(t) {
  let token = {};
  token.raw = t;
  token.header = JSON.parse(atob(t.toString().split('.')[0]));
  token.payload = JSON.parse(atob(t.toString().split('.')[1]));
  return (token);
}

console.log("JWT Decode");
var jwt = jwtDecode(pm.response.json().access_token);
console.log(jwt);

pm.test("Access token to needs to have application roles assigned and granted", function () {
     pm.expect(jwt.payload.roles).to.not.equal(undefined);
});

pm.test("Access token must have 1 role", function () {
     pm.expect(jwt.payload.roles.length).to.equal(1);
});

pm.test("Access token must have XYZ role", function () {
     pm.expect(jwt.payload.roles.includes("XYZ")).to.equal(true);
});

if(jwt.payload.roles !== undefined)
{
    pm.test("Access token - JWT Roles: " + jwt.payload.roles.join(), function(){});
}