silverstripe-framework/tests/php/Security/GroupTest.yml

'SilverStripe\Security\Group':
  admingroup:
    Code: admingroup
  parentgroup:
    Code: parentgroup
  childgroup:
    Code: childgroup
    Parent: '=>SilverStripe\Security\Group.parentgroup'
  grandchildgroup:
    Code: grandchildgroup
    Parent: '=>SilverStripe\Security\Group.childgroup'
  group1:
    Title: Group 1
  group2:
    Title: Group 2
SilverStripe\Security\Tests\GroupTest\TestMember:
  admin:
    FirstName: Admin
    Groups: '=>SilverStripe\Security\Group.admingroup'
  parentgroupuser:
    FirstName: Parent Group User
    Groups: '=>SilverStripe\Security\Group.parentgroup'
  childgroupuser:
    FirstName: Child Group User
    Groups: '=>SilverStripe\Security\Group.childgroup'
  allgroupuser:
    FirstName: All Group User
    Groups:
      - =>SilverStripe\Security\Group.admingroup
      - =>SilverStripe\Security\Group.parentgroup
      - =>SilverStripe\Security\Group.childgroup
'SilverStripe\Security\Permission':
  admincode:
    Code: ADMIN
    Group: '=>SilverStripe\Security\Group.admingroup'