def test(model_engine, testset, local_device, target_dtype, test_batch_size=4):
    """Test the network on the test data.

    Args:
        model_engine (deepspeed.runtime.engine.DeepSpeedEngine): the DeepSpeed engine.
        testset (torch.utils.data.Dataset): the test dataset.
        local_device (str): the local device name.
        target_dtype (torch.dtype): the target datatype for the test data.
        test_batch_size (int): the test batch size.

    """
    # The 10 classes for CIFAR10.
    classes = (
        "plane",
        "car",
        "bird",
        "cat",
        "deer",
        "dog",
        "frog",
        "horse",
        "ship",
        "truck",
    )

    # Define the test dataloader.
    testloader = torch.utils.data.DataLoader(
        testset, batch_size=test_batch_size, shuffle=False, num_workers=0
    )

    # For total accuracy.
    correct, total = 0, 0
    # For accuracy per class.
    class_correct = list(0.0 for i in range(10))
    class_total = list(0.0 for i in range(10))

    # Start testing.
    model_engine.eval()
    with torch.no_grad():
        for data in testloader:
            images, labels = data
            if target_dtype != None:
                images = images.to(target_dtype)
            outputs = model_engine(images.to(local_device))
            _, predicted = torch.max(outputs.data, 1)
            # Count the total accuracy.
            total += labels.size(0)
            correct += (predicted == labels.to(local_device)).sum().item()

            # Count the accuracy per class.
            batch_correct = (predicted == labels.to(local_device)).squeeze()
            for i in range(test_batch_size):
                label = labels[i]
                class_correct[label] += batch_correct[i].item()
                class_total[label] += 1

    if model_engine.local_rank == 0:
        print(
            f"Accuracy of the network on the {total} test images: {100 * correct / total : .0f} %"
        )

        # For all classes, print the accuracy.
        for i in range(10):
            print(
                f"Accuracy of {classes[i] : >5s} : {100 * class_correct[i] / class_total[i] : 2.0f} %"
            )
Test the network on the test data.

    Args:
        model_engine (deepspeed.runtime.engine.DeepSpeedEngine): the DeepSpeed engine.
        testset (torch.utils.data.Dataset): the test dataset.
        local_device (str): the local device name.
        target_dtype (torch.dtype): the target datatype for the test data.
        test_batch_size (int): the test batch size.

    
training/cifar/cifar10_deepspeed.py