diff --git a/test/_utils_internal.py b/test/_utils_internal.py
index 5efa0592068..19deb33546f 100644
--- a/test/_utils_internal.py
+++ b/test/_utils_internal.py
@@ -22,7 +22,6 @@
 from torch import nn, vmap
 
 from torchrl._utils import implement_for, logger, RL_WARNINGS, seed_generator
-from torchrl.data.utils import CloudpickleWrapper
 from torchrl.envs import MultiThreadedEnv, ObservationNorm
 from torchrl.envs.batched_envs import ParallelEnv, SerialEnv
 from torchrl.envs.libs.envpool import _has_envpool
@@ -594,14 +593,6 @@ def check_rollout_consistency_multikey_env(td: TensorDict, max_steps: int):
     assert (td["next", "nested_2", "reward"][~action_is_count] == 0).all()
 
 
-def decorate_thread_sub_func(func, num_threads):
-    def new_func(*args, **kwargs):
-        assert torch.get_num_threads() == num_threads
-        return func(*args, **kwargs)
-
-    return CloudpickleWrapper(new_func)
-
-
 class LSTMNet(nn.Module):
     """An embedder for an LSTM preceded by an MLP.
 
diff --git a/test/test_collectors.py b/test/test_collectors.py
index 1c52fb37615..86a5aa25848 100644
--- a/test/test_collectors.py
+++ b/test/test_collectors.py
@@ -89,6 +89,7 @@
     SafeModule,
 )
 from torchrl.testing.modules import BiasModule, NonSerializableBiasModule
+from torchrl.testing.mp_helpers import decorate_thread_sub_func
 from torchrl.weight_update import (
     MultiProcessWeightSyncScheme,
     SharedMemWeightSyncScheme,
@@ -99,7 +100,6 @@
     from pytorch.rl.test._utils_internal import (
         CARTPOLE_VERSIONED,
         check_rollout_consistency_multikey_env,
-        decorate_thread_sub_func,
         generate_seeds,
         get_available_devices,
         get_default_devices,
@@ -112,7 +112,6 @@
     from _utils_internal import (
         CARTPOLE_VERSIONED,
         check_rollout_consistency_multikey_env,
-        decorate_thread_sub_func,
         generate_seeds,
         get_available_devices,
         get_default_devices,
diff --git a/torchrl/testing/mp_helpers.py b/torchrl/testing/mp_helpers.py
new file mode 100644
index 00000000000..ffc1b3c5a20
--- /dev/null
+++ b/torchrl/testing/mp_helpers.py
@@ -0,0 +1,15 @@
+from __future__ import annotations
+
+import torch
+
+from torchrl.data.utils import CloudpickleWrapper
+
+
+def decorate_thread_sub_func(func, num_threads):
+    """Decorate a function to assert that the number of threads is correct."""
+
+    def new_func(*args, **kwargs):
+        assert torch.get_num_threads() == num_threads
+        return func(*args, **kwargs)
+
+    return CloudpickleWrapper(new_func)