[BugFix] smarter check in set_interaction_type

ghstack-source-id: 1821309ad24827c22c40c41f3544e7a768325f72
Pull Request resolved: #1088

(cherry picked from commit db2b5e6)

tensordict/nn/probabilistic.py

@@ -79,8 +79,11 @@ def __init__(
         self, type: InteractionType | str | None = InteractionType.DETERMINISTIC
     ) -> None:
         super().__init__()
-        if isinstance(type, str):
-            type = InteractionType(type.lower())
+        if not isinstance(type, InteractionType) and type is not None:
+            if isinstance(type, str):
+                type = InteractionType(type.lower())
+            else:
+                raise ValueError(f"{type} is not a valid InteractionType")
         self.type = type
 
     def clone(self) -> set_interaction_type:

test/test_nn.py

@@ -88,9 +88,8 @@ def test_from_str_correct_conversion(self, str_and_expected_type):
 
     @pytest.mark.parametrize("unsupported_type_str", ["foo"])
     def test_from_str_correct_raise(self, unsupported_type_str):
-        with pytest.raises(ValueError) as err:
+        with pytest.raises(ValueError, match=" is not a valid InteractionType"):
             InteractionType.from_str(unsupported_type_str)
-        assert unsupported_type_str in str(err) and "is unsupported" in str(err)
 
 
 class TestTDModule: