tests/models/bitnet/test_modeling_bitnet.py

# Copyright 2025 The BitNet team and 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.
"""Testing suite for the PyTorch BitNet model."""

import gc
import unittest

from transformers import AutoTokenizer, BitNetConfig, is_torch_available
from transformers.testing_utils import (
    backend_empty_cache,
    require_torch,
    slow,
    torch_device,
)

from ...generation.test_utils import GenerationTesterMixin
from ...test_configuration_common import ConfigTester
from ...test_modeling_common import ModelTesterMixin, ids_tensor
from ...test_pipeline_mixin import PipelineTesterMixin


if is_torch_available():
    import torch

    from transformers import (
        BitNetForCausalLM,
        BitNetModel,
    )


class BitNetModelTester:
    def __init__(
        self,
        parent,
        batch_size=13,
        seq_length=7,
        is_training=True,
        use_input_mask=True,
        vocab_size=99,
        hidden_size=64,
        num_hidden_layers=2,
        num_attention_heads=4,
        num_key_value_heads=2,
        intermediate_size=37,
        hidden_act="gelu",
        max_position_embeddings=512,
        initializer_range=0.02,
        pad_token_id=0,
        bos_token_id=1,
        scope=None,
    ):
        self.parent = parent
        self.batch_size = batch_size
        self.seq_length = seq_length
        self.is_training = is_training
        self.use_input_mask = use_input_mask
        self.vocab_size = vocab_size
        self.hidden_size = hidden_size
        self.num_hidden_layers = num_hidden_layers
        self.num_attention_heads = num_attention_heads
        self.num_key_value_heads = num_key_value_heads
        self.intermediate_size = intermediate_size
        self.hidden_act = hidden_act
        self.max_position_embeddings = max_position_embeddings
        self.initializer_range = initializer_range
        self.pad_token_id = pad_token_id
        self.bos_token_id = bos_token_id
        self.scope = scope

    def prepare_config_and_inputs(self):
        input_ids = ids_tensor([self.batch_size, self.seq_length], self.vocab_size)

        input_mask = None
        if self.use_input_mask:
            input_mask = torch.tril(torch.ones_like(input_ids).to(torch_device))

        config = self.get_config()

        return config, input_ids, input_mask

    def get_config(self):
        return BitNetConfig(
            vocab_size=self.vocab_size,
            hidden_size=self.hidden_size,
            num_hidden_layers=self.num_hidden_layers,
            num_attention_heads=self.num_attention_heads,
            num_key_value_heads=self.num_key_value_heads,
            intermediate_size=self.intermediate_size,
            hidden_act=self.hidden_act,
            max_position_embeddings=self.max_position_embeddings,
            initializer_range=self.initializer_range,
            pad_token_id=self.pad_token_id,
            bos_token_id=self.bos_token_id,
        )

    def create_and_check_model(self, config, input_ids, input_mask):
        model = BitNetModel(config=config)
        model.to(torch_device)
        model.eval()
        result = model(input_ids, attention_mask=input_mask)
        result = model(input_ids)
        self.parent.assertEqual(result.last_hidden_state.shape, (self.batch_size, self.seq_length, self.hidden_size))

    def prepare_config_and_inputs_for_common(self):
        config_and_inputs = self.prepare_config_and_inputs()
        (
            config,
            input_ids,
            input_mask,
        ) = config_and_inputs
        inputs_dict = {"input_ids": input_ids, "attention_mask": input_mask}
        return config, inputs_dict


@require_torch
class BitNetModelTest(ModelTesterMixin, GenerationTesterMixin, PipelineTesterMixin, unittest.TestCase):
    all_model_classes = (
        (
            BitNetModel,
            BitNetForCausalLM,
        )
        if is_torch_available()
        else ()
    )
    pipeline_model_mapping = (
        {
            "feature-extraction": BitNetModel,
            "text-generation": BitNetForCausalLM,
        }
        if is_torch_available()
        else {}
    )

    # TODO (ydshieh): Check this. See https://app.circleci.com/pipelines/github/huggingface/transformers/79245/workflows/9490ef58-79c2-410d-8f51-e3495156cf9c/jobs/1012146
    def is_pipeline_test_to_skip(
        self,
        pipeline_test_case_name,
        config_class,
        model_architecture,
        tokenizer_name,
        image_processor_name,
        feature_extractor_name,
        processor_name,
    ):
        return True

    def setUp(self):
        self.model_tester = BitNetModelTester(self)
        self.config_tester = ConfigTester(self, config_class=BitNetConfig, hidden_size=37)

    def test_config(self):
        self.config_tester.run_common_tests()

    def test_model(self):
        config_and_inputs = self.model_tester.prepare_config_and_inputs()
        self.model_tester.create_and_check_model(*config_and_inputs)


@require_torch
class BitNetIntegrationTest(unittest.TestCase):
    @slow
    def test_model_logits(self):
        input_ids = [128000, 128000, 1502, 25, 2650, 527, 499, 30, 128009, 72803, 25, 220]
        model = BitNetForCausalLM.from_pretrained("microsoft/bitnet-b1.58-2B-4T")
        input_ids = torch.tensor([input_ids]).to(model.model.embed_tokens.weight.device)
        with torch.no_grad():
            out = model(input_ids).logits.float().cpu()
        # Expected mean on dim = -1
        EXPECTED_MEAN = torch.tensor(
            [
                [
                    -1.8665,
                    -1.7681,
                    -1.7043,
                    3.7446,
                    2.7730,
                    4.7133,
                    0.9768,
                    -3.5018,
                    -12.2812,
                    -8.1477,
                    -10.2571,
                    -8.7610,
                ]
            ]
        )
        torch.testing.assert_close(out.mean(-1), EXPECTED_MEAN, rtol=1e-2, atol=1e-2)
        # slicing logits[0, 0, 0:30]
        EXPECTED_SLICE = torch.tensor([5.5815, 4.9154, 1.0478, 4.3869, 3.0112, 0.8235, 3.8412, 2.9233, 8.1140, 1.9406, 1.7973, 10.5025, 4.7796, 8.5926, 4.5196, 3.1549, 3.2656, 3.2588, 2.7356, 2.6032, 2.1454, 1.5683, 1.3465, 1.5329, 1.1886, 7.7902, 5.9326, 1.4737, 3.3319, 1.6291])  # fmt: skip
        torch.testing.assert_close(out[0, 0, :30], EXPECTED_SLICE, rtol=1e-4, atol=1e-4)

        del model
        backend_empty_cache(torch_device)
        gc.collect()

    @slow
    def test_model_generation(self):
        EXPECTED_TEXT_COMPLETION = """User: What is your favourite food?Assistant: As an AI, I don't have personal preferences or the ability to eat food. However, I"""
        tokenizer = AutoTokenizer.from_pretrained("microsoft/bitnet-b1.58-2B-4T")
        prompt = tokenizer.apply_chat_template(
            [{"role": "user", "content": "What is your favourite food?"}], add_generation_prompt=True, tokenize=False
        )
        model = BitNetForCausalLM.from_pretrained(
            "microsoft/bitnet-b1.58-2B-4T", device_map="auto", dtype=torch.bfloat16
        )
        input_ids = tokenizer.encode(prompt, return_tensors="pt").to(model.model.embed_tokens.weight.device)

        # greedy generation outputs
        generated_ids = model.generate(input_ids, max_new_tokens=20, do_sample=False)
        text = tokenizer.decode(generated_ids[0], skip_special_tokens=True)
        self.assertEqual(EXPECTED_TEXT_COMPLETION, text)

        del model
        backend_empty_cache(torch_device)
        gc.collect()