spawn multi process to return pythonic dict

Summary: Return pythonic dict from spawn_multi_process

Differential Revision: D52558016

tests/utils/test_timer.py

@@ -284,25 +284,21 @@ def _full_sync_worker_with_timeout(cls, timeout: int) -> bool:
     def test_full_sync_pt_multi_process_check_false(self) -> None:
         mp_dict = spawn_multi_process(2, "gloo", self._full_sync_worker_without_timeout)
         # Both processes should return False
-        self.assertFalse(mp_dict[0])
-        self.assertFalse(mp_dict[1])
+        self.assertDictEqual(mp_dict, {0: False, 1: False})
 
     def test_full_sync_pt_multi_process_check_true(self) -> None:
         mp_dict = spawn_multi_process(2, "gloo", self._full_sync_worker_with_timeout, 8)
         # Both processes should return True
-        self.assertTrue(mp_dict[0])
-        self.assertTrue(mp_dict[1])
+        self.assertDictEqual(mp_dict, {0: True, 1: True})
 
     def test_full_sync_pt_multi_process_edgecase(self) -> None:
         mp_dict = spawn_multi_process(2, "gloo", self._full_sync_worker_with_timeout, 5)
 
         # Both processes should return True
-        self.assertTrue(mp_dict[0])
-        self.assertTrue(mp_dict[1])
+        self.assertDictEqual(mp_dict, {0: True, 1: True})
 
         # Launch 2 worker processes. Each will check time diff >= interval threshold
         mp_dict = spawn_multi_process(2, "gloo", self._full_sync_worker_with_timeout, 4)
 
         # Both processes should return False
-        self.assertFalse(mp_dict[0])
-        self.assertFalse(mp_dict[1])
+        self.assertDictEqual(mp_dict, {0: False, 1: False})

torchtnt/utils/test_utils.py

@@ -130,7 +130,7 @@ def spawn_multi_process(
         p.join()
         tc.assertEqual(p.exitcode, 0)
 
-    return mp_output_dict
+    return mp_output_dict.copy()
 
 
 def init_pg_and_rank_and_launch_test(