tests/test_model_utils.py

# Copyright 2020-2026 The HuggingFace 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
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from transformers import AutoModelForCausalLM

from trl.models.utils import disable_gradient_checkpointing


class TestDisableGradientCheckpointing:
    def test_when_disabled(self):
        model = AutoModelForCausalLM.from_pretrained("trl-internal-testing/tiny-Qwen2ForCausalLM-2.5")
        assert model.is_gradient_checkpointing is False
        with disable_gradient_checkpointing(model):
            assert model.is_gradient_checkpointing is False
        assert model.is_gradient_checkpointing is False

    def test_when_enabled(self):
        model = AutoModelForCausalLM.from_pretrained("trl-internal-testing/tiny-Qwen2ForCausalLM-2.5")
        model.gradient_checkpointing_enable()
        assert model.is_gradient_checkpointing is True
        with disable_gradient_checkpointing(model):
            assert model.is_gradient_checkpointing is False
        assert model.is_gradient_checkpointing is True