diff --git a/meltingpot/testing/mocks_test.py b/meltingpot/testing/mocks_test.py
index 166ad345..7b94b572 100644
--- a/meltingpot/testing/mocks_test.py
+++ b/meltingpot/testing/mocks_test.py
@@ -30,8 +30,8 @@ def test_value_from_specs(self):
     )
     actual = mocks._values_from_specs(specs)
     expected = (
-        {'a': np.zeros([1, 2, 3], dtype=np.uint8) + 0},
-        {'b': np.zeros([1, 2, 3], dtype=np.uint8) + 1},
+        {'a': np.zeros([1, 2, 3], dtype=np.uint8)},
+        {'b': np.ones([1, 2, 3], dtype=np.uint8)},
     )
     np.testing.assert_equal(actual, expected)
 
@@ -44,7 +44,10 @@ def test_mock_substrate(self):
         num_actions=num_actions,
         observation_spec=observation_spec)
 
-    expected_observation = ({'a': np.uint8()}, {'a': np.uint8() + 1})
+    expected_observation = (
+        {'a': np.zeros([], dtype=np.uint8)},
+        {'a': np.ones([], dtype=np.uint8)},
+    )
     expected_reward = tuple(float(n) for n in range(num_players))
 
     with self.subTest('is_substrate'):
diff --git a/meltingpot/utils/policies/saved_model_policy.py b/meltingpot/utils/policies/saved_model_policy.py
index 8df461f3..01fd4ea0 100644
--- a/meltingpot/utils/policies/saved_model_policy.py
+++ b/meltingpot/utils/policies/saved_model_policy.py
@@ -136,7 +136,7 @@ def __init__(self, model_path: str, device_name: str = 'cpu') -> None:
 
   @contextlib.contextmanager
   def _build_context(self):
-    with self._graph.as_default():
+    with self._graph.as_default():  # pylint: disable=not-context-manager
       with tf.compat.v1.device(self._device_name):
         yield