reorganising code and adding test for get_messages_from_spy

nspy.erl

@@ -3,16 +3,46 @@
 -define (NODEBUG, true).
 -include_lib("eunit/include/eunit.hrl").
 
+% API
+% ===
+
 % a test double / mock process to use as a non-replying endpoint (null object) for messages
 mock() -> new([]).
 
+
 % a test spy to wrap another process, monitoring the messages sent to that process and relaying them to the intended receiver
 % doesn't consider node failures or message synchrony, but you probably shouldn't be relying on that anyway.
 wrapper(Target) -> new([Target]).
 
+  passthrough_wrapper_spy_test() ->
+    StuntDouble = nspy:mock(),
+    PassthroughSpy = nspy:wrapper(StuntDouble),
+    PassthroughSpy ! hi,
+    assert_message_received(PassthroughSpy, hi),
+    assert_message_received(StuntDouble, hi).
+
+
+
+%spawn a new spy process with no messages and a list of processes to forward messages to
 new(RelayMessagesTo) ->
   spawn(nspy, spy, [[], RelayMessagesTo]).
 
+
+
+% asks the spy to return its current messages received list
+% n.b. assume asynchronous messaging and use appropriate sleep periods to allow message delivery
+get_messages_from_spy(Spy) ->
+  Spy ! {nspy_list_messages, self()},
+  receive {nspy_messages, Messages} -> Messages end.
+
+  get_messages_from_spy_test() ->
+    Spy = spawn(nspy, spy, [[a_message], []]),
+    ?assertEqual(get_messages_from_spy(Spy), [a_message]). %or timeout failure
+
+
+% CORE
+% ====
+
 spy (Messages, RelayMessagesTo) ->
   receive
     {nspy_list_messages, ReplyTo}  -> 
@@ -26,35 +56,32 @@ spy (Messages, RelayMessagesTo) ->
       spy([Message | Messages], RelayMessagesTo)
   end.
 
+
+
+
+
+% ASSERTS
+% =======
+
 assert_message_received(Spy, Expected) ->
   Messages = get_messages_from_spy(Spy),
   io:format("~n[SPY] expected ~p received ~p~n", [Expected, Messages]),
   MessageFound = lists:any(fun(Elem) -> Elem =:= Expected end, Messages),
   ?assert(MessageFound).
 
-get_messages_from_spy(Spy) ->
-  Spy ! {nspy_list_messages, self()},
-  receive {nspy_messages, Messages} -> Messages end.
+  assert_message_received_success_test() ->
+    Spy = nspy:mock(),
+    Spy ! hi,
+    Spy ! ho,
+    timer:sleep(200),
+    assert_message_received(Spy, hi),
+    assert_message_received(Spy, ho).
+
+  assert_message_received_failure_test() ->
+    Spy = nspy:mock(),
+    Spy ! hi,
+    timer:sleep(200),
+    ?assertError({assertion_failed, _}, assert_message_received(Spy, ho)).
 
 
-assert_message_received_success_test() ->
-  Spy = nspy:mock(),
-  Spy ! hi,
-  Spy ! ho,
-  timer:sleep(200),
-  assert_message_received(Spy, hi),
-  assert_message_received(Spy, ho).
-
-assert_message_received_failure_test() ->
-  Spy = nspy:mock(),
-  Spy ! hi,
-  timer:sleep(200),
-  ?assertError({assertion_failed, _}, assert_message_received(Spy, ho)).
-
-passthrough_spy_test() ->
-  StuntDouble = nspy:mock(),
-  PassthroughSpy = nspy:wrapper(StuntDouble),
-  PassthroughSpy ! hi,
-  assert_message_received(PassthroughSpy, hi),
-  assert_message_received(StuntDouble, hi).