anchor.diff:      verify_messages_present(Context#subs_ctx{users = [?ID(u1)]}, [
           expectation(?ID(u1), U1),
           expectation(?ID(g1), G1),
  +        expectation(?ID(g2), G2),
  +        expectation(?ID(g3), G3),
           expectation(?ID(s1), S1),
           expectation(?ID(s2), S2)
       ]),
  
positive.code:     % given
      [Node | _] = ?config(oz_worker_nodes, Config),
      PID = create_provider(Node, ?ID(p1), [?ID(s1), ?ID(s2)]),
      U1 = #onedata_user{name = <<"u1">>, groups = [?ID(g1)], spaces = [?ID(s2)]},
      G1 = #user_group{name = <<"g1">>, users = [{?ID(u1), []}], spaces = [?ID(s1)]},
      S1 = #space{name = <<"s1">>, providers_supports = [{PID, 0}], groups = [{?ID(g1), []}]},
      S2 = #space{name = <<"s2">>, providers_supports = [{PID, 0}], users = [{?ID(u1), []}]},
      save(Node, ?ID(u1), U1),
      save(Node, ?ID(g1), G1),
      save(Node, ?ID(s1), S1),
      save(Node, ?ID(s2), S2),
  
  
negative.code:     call_worker(Node, {update_missing_seq, ProviderID, ResumeAt, Missing}),
      All = lists:append(get_messages()),
  
      ct:run("~p", [All, Expected, Forbidden]),
  
      Seqs = extract_seqs(All),
      NextResumeAt = largest([ResumeAt | Seqs]),
      NewExpectedSeqs = new_expected_seqs(NextResumeAt, ResumeAt),
  