Improve test_runner performance: O(n²) → O(n) test grouping and fix ct_hooks collection

Summary: Replace the O(n²) add_or_append/2 function in get_requested_tests/1 with a map-based accumulator that preserves insertion order in O(n) time. Also fix getCtHook/3 to use lists:partition/2 instead of lists:splitwith/2, which would miss non-contiguous ct_hooks entries in the options list.

Reviewed By: jcpetruzza

Differential Revision: D95046286

fbshipit-source-id: c50aba5cf10a2271fd301ac5be12754086253a9e

Author: TD5

prelude/erlang/common_test/test_binary/src/test_runner.erl

@@ -370,28 +370,21 @@ g1.t1, g2.t2, g1.t2, g1.t3, g2.t2, we produce:
 """.
 -spec get_requested_tests([#ct_test{}]) -> [{[atom()], [atom()]}].
 get_requested_tests(Tests) ->
-    lists:foldl(
-        fun(Test, List) ->
+    {TestMap, RevOrderedKeys} = lists:foldl(
+        fun(Test, {Map, Keys}) ->
             Groups = Test#ct_test.groups,
-            add_or_append(List, {Groups, Test#ct_test.test_name})
+            TestName = Test#ct_test.test_name,
+            case Map of
+                #{Groups := Existing} ->
+                    {Map#{Groups => [TestName | Existing]}, Keys};
+                _ ->
+                    {Map#{Groups => [TestName]}, [Groups | Keys]}
+            end
         end,
-        [],
+        {#{}, []},
         Tests
-    ).
-
--spec add_or_append(list({K, list(V)}), {K, V}) -> list({K, list(V)}).
-add_or_append(List, {Key, Value}) ->
-    List0 = lists:map(
-        fun
-            ({Key0, Value0}) when Key0 =:= Key -> {Key0, lists:append(Value0, [Value])};
-            (Other) -> Other
-        end,
-        List
     ),
-    case List0 =:= List of
-        true -> lists:append(List0, [{Key, [Value]}]);
-        false -> List0
-    end.
+    [{Key, lists:reverse(maps:get(Key, TestMap))} || Key <- lists:reverse(RevOrderedKeys)].
 
 -doc """
 Built the test_spec selecting the requested tests and
@@ -435,7 +428,7 @@ Collect all the ct_hooks entries provided by the user, and add the cth_tpx hook
     CtHooks :: {ct_hooks, [term()]},
     CtOpts1 :: [term()].
 getCtHook(CtOpts0, ResultOutput, ProgressLineFingerprint) ->
-    {CtHooksOpts, CtOpts1} = lists:splitwith(
+    {CtHooksOpts, CtOpts1} = lists:partition(
         fun
             ({ct_hooks, _}) -> true;
             (_) -> false