Ignore padded GR00T N1.7 RTC prefix rows

tests/policies/groot/test_groot_n1_7.py

@@ -458,6 +458,39 @@ def test_groot_predict_action_chunk_forwards_n1_7_rtc_prefix(monkeypatch):
     torch.testing.assert_close(dummy_model.forward_inputs["action"][0, :, 7:], torch.zeros(8, 125))
 
 
+def test_groot_predict_action_chunk_strips_padded_n1_7_rtc_prefix(monkeypatch):
+    from lerobot.policies.groot.groot_n1_7 import GR00TN17
+
+    dummy_model = _DummyGrootModel()
+    monkeypatch.setattr(GR00TN17, "from_pretrained", classmethod(lambda cls, **kwargs: dummy_model))
+    config = _groot_config(GROOT_N1_7)
+    policy = GrootPolicy(config)
+    policy.config.rtc_config = SimpleNamespace(execution_horizon=6)
+
+    prev_chunk = torch.cat(
+        (
+            torch.arange(4 * 7, dtype=torch.float32).view(4, 7) + 1.0,
+            torch.zeros(2, 7),
+        )
+    )
+
+    policy.predict_action_chunk(
+        {"state": torch.zeros(1, 1, 132)},
+        inference_delay=5,
+        prev_chunk_left_over=prev_chunk,
+    )
+
+    assert dummy_model.get_action_options == {
+        "action_horizon": 4,
+        "rtc_overlap_steps": 4,
+        "rtc_frozen_steps": 4,
+        "rtc_ramp_rate": 6.0,
+    }
+    assert dummy_model.forward_inputs["action"].shape == (1, 4, 132)
+    torch.testing.assert_close(dummy_model.forward_inputs["action"][0, :, :7], prev_chunk[:4])
+    torch.testing.assert_close(dummy_model.forward_inputs["action"][0, :, 7:], torch.zeros(4, 125))
+
+
 def test_groot_n1_7_predict_action_chunk_truncates_to_checkpoint_valid_horizon(tmp_path, monkeypatch):
     from lerobot.policies.groot.groot_n1_7 import GR00TN17