[Test] tests for BinarizeReward (#302)

Author: srikanthmg85

test/test_transforms.py

@@ -31,6 +31,7 @@
     CatTensors,
     FlattenObservation,
     RewardScaling,
+    BinarizeReward,
 )
 from torchrl.envs.libs.gym import _has_gym
 from torchrl.envs.transforms import VecNorm, TransformedEnv
@@ -874,8 +875,27 @@ def test_noop_reset_env(self, random, device, compose):
             assert transformed_env.step_count == 30
 
     @pytest.mark.parametrize("device", get_available_devices())
-    def test_binerized_reward(self, device):
-        pass
+    @pytest.mark.parametrize("batch", [[], [4], [6, 4]])
+    def test_binarized_reward(self, device, batch):
+        torch.manual_seed(0)
+        br = BinarizeReward()
+        reward = torch.randn(*batch, 1, device=device)
+        reward_copy = reward.clone()
+        misc = torch.randn(*batch, 1, device=device)
+        misc_copy = misc.clone()
+
+        td = TensorDict(
+            {
+                "misc": misc,
+                "reward": reward,
+            },
+            batch,
+        )
+        br(td)
+        assert td["reward"] is reward
+        assert (td["reward"] != reward_copy).all()
+        assert (td["misc"] == misc_copy).all()
+        assert (torch.count_nonzero(td["reward"]) == torch.sum(reward_copy > 0)).all()
 
     @pytest.mark.parametrize("batch", [[], [2], [2, 4]])
     @pytest.mark.parametrize("scale", [0.1, 10])