_: {
  outputs = [ ]; # no outputs registered
  modules = [
    (_: {
      config = {
        checks.expr =
          assert 2 + 2 == 5; # checks output not registered -- no fail
          null;
      };
    })
  ];
  fails = false;
  expectedOutput = { }; # AGENT: do not edit, I will fill in the produced output
}