[Test refactor 1/5] Per-folder tests reorganization (#15725)

* Per-folder tests reorganization

Co-authored-by: sgugger <sylvain.gugger@gmail.com>
Co-authored-by: Stas Bekman <stas@stason.org>

tests/trainer/test_trainer_distributed.py

@@ -0,0 +1,143 @@
+# Copyright 2020 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
+# limitations under the License.
+
+import sys
+from typing import Dict
+
+from transformers import EvalPrediction, HfArgumentParser, TrainingArguments, is_torch_available
+from transformers.testing_utils import (
+    TestCasePlus,
+    execute_subprocess_async,
+    get_torch_dist_unique_port,
+    require_torch_multi_gpu,
+)
+from transformers.utils import logging
+
+
+logger = logging.get_logger(__name__)
+
+
+if is_torch_available():
+    import torch
+    from torch import nn
+    from torch.utils.data import Dataset
+
+    from transformers import Trainer
+
+    class DummyDataset(Dataset):
+        def __init__(self, length: int = 101):
+            self.length = length
+
+        def __len__(self):
+            return self.length
+
+        def __getitem__(self, i) -> int:
+            return i
+
+    class DummyDataCollator:
+        def __call__(self, features):
+            return {"input_ids": torch.tensor(features), "labels": torch.tensor(features)}
+
+    class DummyModel(nn.Module):
+        def __init__(self):
+            super().__init__()
+            # Add some (unused) params otherwise DDP will complain.
+            self.fc = nn.Linear(120, 80)
+
+        def forward(self, input_ids, labels=None):
+            if labels is not None:
+                return torch.tensor(0.0, device=input_ids.device), input_ids
+            else:
+                return input_ids
+
+
+class TestTrainerDistributed(TestCasePlus):
+    @require_torch_multi_gpu
+    def test_trainer(self):
+
+        distributed_args = f"""
+            -m torch.distributed.launch
+            --nproc_per_node={torch.cuda.device_count()}
+            --master_port={get_torch_dist_unique_port()}
+            {self.test_file_dir}/test_trainer_distributed.py
+        """.split()
+        output_dir = self.get_auto_remove_tmp_dir()
+        args = f"--output_dir {output_dir}".split()
+        cmd = [sys.executable] + distributed_args + args
+        execute_subprocess_async(cmd, env=self.get_env())
+        # successful return here == success - any errors would have caused an error in the sub-call
+
+
+if __name__ == "__main__":
+    # The script below is meant to be run under torch.distributed, on a machine with multiple GPUs:
+    #
+    # PYTHONPATH="src" python -m torch.distributed.launch --nproc_per_node 2 --output_dir output_dir ./tests/test_trainer_distributed.py
+
+    parser = HfArgumentParser((TrainingArguments,))
+    training_args = parser.parse_args_into_dataclasses()[0]
+
+    logger.warning(
+        f"Process rank: {training_args.local_rank}, device: {training_args.device}, n_gpu: {training_args.n_gpu}, "
+        f"distributed training: {training_args.local_rank != -1}"
+    )
+
+    # Essentially, what we want to verify in the distributed case is that we get all samples back,
+    # in the right order. (this is crucial for prediction for instance)
+    for dataset_length in [101, 40, 7]:
+        dataset = DummyDataset(dataset_length)
+
+        def compute_metrics(p: EvalPrediction) -> Dict:
+            sequential = list(range(len(dataset)))
+            success = p.predictions.tolist() == sequential and p.label_ids.tolist() == sequential
+            if not success and training_args.local_rank == 0:
+                logger.warning(
+                    "Predictions and/or labels do not match expected results:\n  - predictions: "
+                    f"{p.predictions.tolist()}\n  - labels: {p.label_ids.tolist()}\n  - expected: {sequential}"
+                )
+            return {"success": success}
+
+        trainer = Trainer(
+            model=DummyModel(),
+            args=training_args,
+            data_collator=DummyDataCollator(),
+            eval_dataset=dataset,
+            compute_metrics=compute_metrics,
+        )
+        metrics = trainer.evaluate()
+        logger.info(metrics)
+        if metrics["eval_success"] is not True:
+            logger.error(metrics)
+            exit(1)
+
+        p = trainer.predict(dataset)
+        logger.info(p.metrics)
+        if p.metrics["test_success"] is not True:
+            logger.error(p.metrics)
+            exit(1)
+
+        trainer.args.eval_accumulation_steps = 2
+
+        metrics = trainer.evaluate()
+        logger.info(metrics)
+        if metrics["eval_success"] is not True:
+            logger.error(metrics)
+            exit(1)
+
+        p = trainer.predict(dataset)
+        logger.info(p.metrics)
+        if p.metrics["test_success"] is not True:
+            logger.error(p.metrics)
+            exit(1)
+
+        trainer.args.eval_accumulation_steps = None