Add assert_configurable_module info config_parse_SUITE

It will save a lot of time next time people would add a new module
Previous behaviour would just ignore any parameters and make an error
in deeply nested code. That would confuse people a lot.

Default behaviour is to ignore config_spec even if it is defined.
Unless module is listed in a separate module list.

Fix mod_fast_auth_token config tests.

src/config/mongoose_config_spec.erl

@@ -32,6 +32,10 @@
          process_domain_cert/1,
          process_infinity_as_zero/1]).
 
+%% For tests
+-export([configurable_modules/0]).
+-ignore_xref([configurable_modules/0]).
+
 -include("mongoose_config_spec.hrl").
 
 -type config_node() :: config_section() | config_list() | config_option().
@@ -753,6 +757,7 @@ configurable_modules() ->
      mod_disco,
      mod_event_pusher,
      mod_extdisco,
+     mod_fast_auth_token,
      mod_global_distrib,
      mod_http_upload,
      mod_inbox,

test/config_parser_SUITE.erl

@@ -3118,8 +3118,22 @@ check_iqdisc(ParentP, ParentT) when is_function(ParentT, 1) ->
 
 check_module_defaults(Mod) ->
     ExpectedCfg = default_mod_config(Mod),
+    case maps:size(ExpectedCfg) of
+        0 ->
+            ok;
+        _ ->
+            assert_configurable_module(mod_fast_auth_token)
+    end,
     ?cfgh([modules, Mod], ExpectedCfg, #{<<"modules">> => #{atom_to_binary(Mod) => #{}}}).
 
+assert_configurable_module(Module) ->
+    case lists:member(Module, mongoose_config_spec:configurable_modules()) of
+        true -> ok;
+        false ->
+            ct:fail({assert_configurable_module, Module,
+                     "Don't forget to add module into mongoose_config_spec:configurable_modules/1"})
+    end.
+
 %% helpers for 'listen' tests
 
 listener(Type, Opts) ->