TestKit for Erlang - testing

Question

Is there any kind of test framework for Erlang which is similar to TestKit in Akka?
The goal is to test processes in an integrated environment, for example, to send some messages to a group of processes on one end and assert the resulting messages coming out on the other end. The Akka Testkit makes these kinds of tests fairly straightforward, but I have not been able to find the equivalent in Erlang yet.
EDIT: as the simplest example of what I'm looking for, let's say that we have a process A that is expected to send a message to process B, and I would like to test this behaviour.
In Akka, I can instantiate an actor based on the TestKit class, which has a builtin method expectMsg. So my test looks like this:
instantiate a mock B actor
instantiate the A actor (which gets a reference to B somehow)
send B a message
call B.expectMsg to verify that it received the message (note that
this automatically makes sure that no other type of message is sent to B, and
you can optionally provide a timeout)
Is there a library that supports this kind of workflow in Erlang? As far as I know neither EUnit nor CT support this kind of testing.
To get an idea of the more complex assertions, please see this page: http://doc.akka.io/api/akka/2.0/akka/testkit/TestKit.html

Answer 1

Erlang itself makes these kinds of tests fairly straightforward. There is Lightweight Unit Testing Framework for Erlang eunit and there is Common Test framework for high scale integration testing.
Edit:
You don't need nothing more than Erlang for such simple things:
$ cat echo.erl
-module(echo).
-export([start/0, send/3]).
start() ->
spawn_link(fun() ->
receive
{To, Msg} -> To ! Msg
end
end).
send(Echo, To, Msg) ->
Echo ! {To, Msg}.
-include_lib("eunit/include/eunit.hrl").
echo_test_() ->
Msg = "Hello world!",
{timeout, 0.1, fun() ->
Echo = echo:start(),
echo:send(Echo, self(), Msg),
?assertEqual(Msg, receive X -> X end)
end}.
$ erlc echo.erl
$ erl
Erlang/OTP 18 [erts-7.0] [source] [64-bit] [smp:4:4] [async-threads:10] [hipe] [kernel-poll:false]
Eshell V7.0 (abort with ^G)
1> eunit:test(echo, [verbose]).
======================== EUnit ========================
echo: echo_test_ (module 'echo')...ok
=======================================================
Test passed.
ok
2>
Process A is started by echo:start/0 and process B is testing process itself. If you want mock existing modules there is meck. If you would like just watch messages between two processes without messing with receiver code, you can of course use tracing capabilities of Erlang VM itself.