[BugFix] Fix collector with no buffers and devices

ghstack-source-id: 89bc0df
Pull Request resolved: #2809

Author: Vincent Moens

test/test_collector.py

@@ -3093,16 +3093,23 @@ def test_dynamic_sync_collector(self):
             assert isinstance(data, LazyStackedTensorDict)
             assert data.names[-1] == "time"
 
-    def test_dynamic_multisync_collector(self):
+    @pytest.mark.parametrize("policy_device", [None, *get_default_devices()])
+    def test_dynamic_multisync_collector(self, policy_device):
         env = EnvWithDynamicSpec
-        policy = RandomPolicy(env().action_spec)
+        spec = env().action_spec
+        if policy_device is not None:
+            spec = spec.to(policy_device)
+        policy = RandomPolicy(spec)
         collector = MultiSyncDataCollector(
             [env],
             policy,
             frames_per_batch=20,
             total_frames=100,
             use_buffers=False,
             cat_results="stack",
+            policy_device=policy_device,
+            env_device="cpu",
+            storing_device="cpu",
         )
         for data in collector:
             assert isinstance(data, LazyStackedTensorDict)