fix test for flat dict structure

tests/rl/test_sac_algorithm.py

@@ -165,30 +165,32 @@ def test_training_stats_defaults():
 def test_get_weights_returns_policy_state_dict():
     algorithm, policy = _make_algorithm()
     weights = algorithm.get_weights()
-    for key in policy.state_dict():
-        assert key in weights
-        assert torch.equal(weights[key].cpu(), policy.state_dict()[key].cpu())
+    assert "policy" in weights
+    actor_state_dict = policy.actor.state_dict()
+    for key in actor_state_dict:
+        assert key in weights["policy"]
+        assert torch.equal(weights["policy"][key].cpu(), actor_state_dict[key].cpu())
 
 
 def test_get_weights_includes_discrete_critic_when_present():
-    algorithm, policy = _make_algorithm(num_discrete_actions=3, action_dim=6)
+    algorithm, _ = _make_algorithm(num_discrete_actions=3, action_dim=6)
     weights = algorithm.get_weights()
-    dc_keys = [k for k in weights if k.startswith("discrete_critic.")]
-    assert len(dc_keys) > 0
+    assert "discrete_critic" in weights
+    assert len(weights["discrete_critic"]) > 0
 
 
 def test_get_weights_excludes_discrete_critic_when_absent():
     algorithm, _ = _make_algorithm()
     weights = algorithm.get_weights()
-    dc_keys = [k for k in weights if k.startswith("discrete_critic.")]
-    assert len(dc_keys) == 0
+    assert "discrete_critic" not in weights
 
 
 def test_get_weights_are_on_cpu():
-    algorithm, _ = _make_algorithm()
+    algorithm, _ = _make_algorithm(num_discrete_actions=3, action_dim=6)
     weights = algorithm.get_weights()
-    for key, tensor in weights.items():
-        assert tensor.device == torch.device("cpu"), f"{key} is not on CPU"
+    for group_name, state_dict in weights.items():
+        for key, tensor in state_dict.items():
+            assert tensor.device == torch.device("cpu"), f"{group_name}/{key} is not on CPU"
 
 
 # ===========================================================================
@@ -408,10 +410,11 @@ def test_load_weights_round_trip():
     weights = algo_src.get_weights()
     algo_dst.load_weights(weights, device="cpu")
 
-    for key in weights:
+    dst_actor_state_dict = algo_dst.policy.actor.state_dict()
+    for key, tensor in weights["policy"].items():
         assert torch.equal(
-            algo_dst.policy.state_dict()[key].cpu(),
-            weights[key].cpu(),
+            dst_actor_state_dict[key].cpu(),
+            tensor.cpu(),
         ), f"Policy param '{key}' mismatch after load_weights"
 
 
@@ -426,12 +429,13 @@ def test_load_weights_round_trip_with_discrete_critic():
     weights = algo_src.get_weights()
     algo_dst.load_weights(weights, device="cpu")
 
-    dc_keys = [k for k in weights if k.startswith("discrete_critic.")]
-    assert len(dc_keys) > 0
-    for key in dc_keys:
+    assert "discrete_critic" in weights
+    assert len(weights["discrete_critic"]) > 0
+    dst_dc_state_dict = algo_dst.discrete_critic.state_dict()
+    for key, tensor in weights["discrete_critic"].items():
         assert torch.equal(
-            algo_dst.policy.state_dict()[key].cpu(),
-            weights[key].cpu(),
+            dst_dc_state_dict[key].cpu(),
+            tensor.cpu(),
         ), f"Discrete critic param '{key}' mismatch after load_weights"