def METHOD_NAME(self):
    memship = self.portal.portal_membership
    context = self.portal
    member = memship.getMemberById(PloneTestCase.default_user)
    # Login name and user name start out the same
    found = get_member_by_login_name(context, PloneTestCase.default_user)
    self.assertEqual(member.id, found.id)
    # Change the login name:
    set_own_login_name(member, "vanrees")
    # A member with this user name is still returned:
    found = get_member_by_login_name(context, PloneTestCase.default_user)
    self.assertEqual(member.id, found.id)
    # With the changed login name we can find the member:
    found = get_member_by_login_name(context, "vanrees")
    self.assertEqual(member.id, found.id)
    # Demonstrate that we can find other members than just the
    # default user:
    found = get_member_by_login_name(context, SITE_OWNER_NAME)
    member = memship.getMemberById(SITE_OWNER_NAME)
    self.assertEqual(member.id, found.id)