fix(vlabench): align gripper action range

tests/envs/test_vlabench_env.py

@@ -0,0 +1,40 @@
+#!/usr/bin/env python
+
+# Copyright 2025 The HuggingFace Inc. team. All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import numpy as np
+
+from lerobot.envs.vlabench import ACTION_HIGH, ACTION_LOW, VLABenchEnv
+
+
+def test_vlabench_action_space_uses_zero_to_one_gripper_channel():
+    env = VLABenchEnv()
+
+    np.testing.assert_array_equal(env.action_space.low, ACTION_LOW)
+    np.testing.assert_array_equal(env.action_space.high, ACTION_HIGH)
+    assert env.action_space.shape == (7,)
+    assert env.action_space.low[-1] == 0.0
+    assert env.action_space.high[-1] == 1.0
+    np.testing.assert_array_equal(env.action_space.low[:6], np.full(6, -1.0, dtype=np.float32))
+    np.testing.assert_array_equal(env.action_space.high[:6], np.full(6, 1.0, dtype=np.float32))
+
+
+def test_vlabench_gripper_action_normalization_keeps_backward_compatibility():
+    assert VLABenchEnv._normalize_gripper_action(-1.0) == 0.0
+    assert VLABenchEnv._normalize_gripper_action(-0.5) == 0.25
+    assert VLABenchEnv._normalize_gripper_action(0.0) == 0.0
+    assert VLABenchEnv._normalize_gripper_action(0.5) == 0.5
+    assert VLABenchEnv._normalize_gripper_action(1.0) == 1.0
+    assert VLABenchEnv._normalize_gripper_action(1.5) == 1.0