Unified Auditing policy - no results in unified_audit_trail

I need to create unified audit policy to audit all privileges granted to a role and enable it for certain users.
I completed the steps below and I don't get the audit records in the unified_audit_trail.
What can be wrong here?

1) I have unified auditing enabled.

select value from v$option where parameter = 'Unified Auditing';

VALUE
TRUE

2) I created testrole and testuser:

create table Table1 (a1 int, a2 int);
insert into table1 values (1,2);
commit;

create role testrole;
grant connect to testrole;
grant select on table1 to testrole;

create user testuser identified by testuser123;
grant testrole to testuser;

3) Created and enabled unified policy by testuser: