Why do no third party assertion libraries exist for Common Test?

When writing tests I find myself writing all kinds of small little helper functions to make assertions. I searched for an assertion library and didn't find anything. In my tests I often have things like this:

value_in_list(_Value, []) ->
  false;
value_in_list(Value, [Item|List]) ->
  case Value == Item of
    true ->
      true;
    false ->
      value_in_list(Value, List)
  end.

test_start_link(_Config) ->
  % should return the pid and register the process as my_app
  {ok, Pid} = my_app:start_link(),
  true = is_pid(Pid),
  value_in_list(my_app, registered()).

I end up having to write a whole function to check if my_app is a registered process. It would be much nicer if I could just call something like assertion:value_in_list(my_app, registered()) or assertion:is_registered(my_app).

I come from a Ruby background so I hate having to clutter up my tests with utility functions just to make a few assertions. It would be much cleaner if I could just do:

test_start_link(_Config) ->
  % should return the pid and register the process as my_app
  {ok, Pid} = my_app:start_link(),
  true = is_pid(Pid),
  assertion:value_in_list(my_app, registered()).

So my questions are:

• Why doesn't an assertion library exist for Common Test?
• Would it be possible to build a third party library that would be accessible during all tests?

I decided to write an Erlang assertion library to help with cases like this. It provides this functionality.