Prettify all of common test output.

This uses cth_readable to:
- silence error_logger output to the shell unless a test fails
- silence ct:pal output to the shell unless a test fails

I have currently not baked in any way to disable this behaviour, but I
figured if it is required, there is time to do it before the final
3.0.0 release.

rebar.config

@@ -8,7 +8,8 @@
         {getopt,              "0.8.2"},
         {bbmustache,          "1.0.4"},
         {relx,                "3.8.0"},
-        {cf,                  "0.1.3"}]}.
+        {cf,                  "0.1.3"},
+        {cth_readable,        "1.0.0"}]}.
 
 {escript_name, rebar3}.
 {escript_emu_args, "%%! +sbtu +A0\n"}.

rebar.lock

@@ -1,6 +1,7 @@
 [{<<"bbmustache">>,{pkg,<<"bbmustache">>,<<"1.0.4">>},0},
  {<<"certifi">>,{pkg,<<"certifi">>,<<"0.1.1">>},0},
  {<<"cf">>,{pkg,<<"cf">>,<<"0.1.3">>},0},
+ {<<"cth_readable">>,{pkg,<<"cth_readable">>,<<"1.0.0">>},0},
  {<<"erlware_commons">>,{pkg,<<"erlware_commons">>,<<"0.16.0">>},0},
  {<<"getopt">>,{pkg,<<"getopt">>,<<"0.8.2">>},0},
  {<<"providers">>,{pkg,<<"providers">>,<<"1.5.0">>},0},

src/rebar_prv_common_test.erl

@@ -152,7 +152,7 @@ split_string(String) ->
 
 cfgopts(State) ->
     Opts = rebar_state:get(State, ct_opts, []),
-    rebar_utils:filtermap(fun filter_opts/1, Opts).
+    add_hooks(rebar_utils:filtermap(fun filter_opts/1, Opts)).
 
 filter_opts({test_spec, _}) ->
     ?WARN("Test specs not supported", []),
@@ -170,6 +170,18 @@ filter_opts({suite, Suites}) ->
                              Suites)}};
 filter_opts(_) -> true.
 
+add_hooks(Opts) ->
+    %% cth_readable hooks
+    case lists:keyfind(ct_hooks, 1, Opts) of
+        false ->
+            [{ct_hooks, [cth_readable_failonly, cth_readable_shell]} | Opts];
+        {ct_hooks, Hooks} ->
+            %% Make sure hooks are there once only.
+            ReadableHooks = [cth_readable_failonly, cth_readable_shell],
+            NewHooks =  (Hooks -- ReadableHooks) ++ ReadableHooks,
+            lists:keyreplace(ct_hooks, 1, Opts, {ct_hooks, NewHooks})
+    end.
+
 select_tests(State, ProjectApps, CmdOpts, CfgOpts) ->
     FixedOpts = lists:filter(fun({_, _}) -> true; (V) -> ?WARN("`~p` is not a valid option for `ct_opts`", [V]) end, CfgOpts),
     Merged = lists:ukeymerge(1,
@@ -249,7 +261,7 @@ inject(Opts, State) ->
     %% append `ct_compile_opts` to app defined `erl_opts`
     ErlOpts = rebar_opts:get(Opts, erl_opts, []),
     CTOpts = rebar_state:get(State, ct_compile_opts, []),
-    NewErlOpts = CTOpts ++ ErlOpts,
+    NewErlOpts = add_transforms(CTOpts) ++ ErlOpts,
     %% append `ct_first_files` to app defined `erl_first_files`
     FirstFiles = rebar_opts:get(Opts, erl_first_files, []),
     CTFirstFiles = rebar_state:get(State, ct_first_files, []),
@@ -259,6 +271,11 @@ inject(Opts, State) ->
                 Opts,
                 [{erl_opts, NewErlOpts}, {erl_first_files, NewFirstFiles}]).
 
+add_transforms(CTOpts) ->
+    ReadableTransform = [{parse_transform, cth_readable_transform}],
+    (CTOpts -- ReadableTransform) ++ ReadableTransform.
+
+
 test_dirs(State, Apps, Opts) ->
     case {proplists:get_value(suite, Opts), proplists:get_value(dir, Opts)} of
         {Suites, undefined} -> set_compile_dirs(State, Apps, {suite, Suites});