testing_utils.py

# 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 contextlib
import importlib.util
import inspect
import logging
import numpy as np
import os
import random
import re
import shutil
import sys
import tempfile
import unittest

from distutils.util import strtobool
from io import StringIO
from packaging import version
from pathlib import Path
from typing import Iterator, Union
from unittest import mock
from unittest.case import SkipTest


try:
    import torch
    _torch_available = True
except:
    _torch_available = False

def is_torch_available():
    return _torch_available

def parse_flag_from_env(key, default=False):
    try:
        value = os.environ[key]
    except KeyError:
        # KEY isn't set, default to `default`.
        _value = default
    else:
        # KEY is set, convert it to True or False.
        try:
            _value = strtobool(value)
        except ValueError:
            # More values are supported, but let's keep the message simple.
            raise ValueError(f"If set, {key} must be yes or no.")
    return _value


def parse_int_from_env(key, default=None):
    try:
        value = os.environ[key]
    except KeyError:
        _value = default
    else:
        try:
            _value = int(value)
        except ValueError:
            raise ValueError(f"If set, {key} must be a int.")
    return _value


def require_torch(test_case):
    """
    Decorator marking a test that requires PyTorch.

    These tests are skipped when PyTorch isn't installed.

    """
    if not is_torch_available():
        return unittest.skip("test requires PyTorch")(test_case)
    else:
        return test_case



def require_torch_multi_gpu(test_case):
    """
    Decorator marking a test that requires a multi-GPU setup (in PyTorch). These tests are skipped on a machine without
    multiple GPUs.

    To run *only* the multi_gpu tests, assuming all test names contain multi_gpu: $ pytest -sv ./tests -k "multi_gpu"
    """
    if not is_torch_available():
        return unittest.skip("test requires PyTorch")(test_case)

    import torch

    if torch.cuda.device_count() < 2:
        return unittest.skip("test requires multiple GPUs")(test_case)
    else:
        return test_case


def require_torch_non_multi_gpu(test_case):
    """
    Decorator marking a test that requires 0 or 1 GPU setup (in PyTorch).
    """
    if not is_torch_available():
        return unittest.skip("test requires PyTorch")(test_case)

    import torch

    if torch.cuda.device_count() > 1:
        return unittest.skip("test requires 0 or 1 GPU")(test_case)
    else:
        return test_case


def require_torch_up_to_2_gpus(test_case):
    """
    Decorator marking a test that requires 0 or 1 or 2 GPU setup (in PyTorch).
    """
    if not is_torch_available():
        return unittest.skip("test requires PyTorch")(test_case)

    import torch

    if torch.cuda.device_count() > 2:
        return unittest.skip("test requires 0 or 1 or 2 GPUs")(test_case)
    else:
        return test_case


def require_torch_tpu(test_case):
    """
    Decorator marking a test that requires a TPU (in PyTorch).
    """
    if not is_torch_tpu_available():
        return unittest.skip("test requires PyTorch TPU")
    else:
        return test_case


if is_torch_available():
    # Set env var CUDA_VISIBLE_DEVICES="" to force cpu-mode
    import torch

    torch_device = "cuda" if torch.cuda.is_available() else "cpu"
else:
    torch_device = None


def require_torch_gpu(test_case):
    """Decorator marking a test that requires CUDA and PyTorch."""
    if torch_device != "cuda":
        return unittest.skip("test requires CUDA")(test_case)
    else:
        return test_case


def require_datasets(test_case):
    """Decorator marking a test that requires datasets."""

    if not is_datasets_available():
        return unittest.skip("test requires `datasets`")(test_case)
    else:
        return test_case

def is_deepspeed_available():
    return importlib.util.find_spec("deepspeed") is not None

def require_deepspeed(test_case):
    """
    Decorator marking a test that requires deepspeed
    """
    if not is_deepspeed_available():
        return unittest.skip("test requires deepspeed")(test_case)
    else:
        return test_case

def is_bnb_available():
    return importlib.util.find_spec("bitsandbytes") is not None

def require_bnb(test_case):
    """
    Decorator marking a test that requires bitsandbytes
    """
    if not is_bnb_available():
        return unittest.skip("test requires bitsandbytes from https://github.com/facebookresearch/bitsandbytes")(test_case)
    else:
        return test_case


def require_bnb_non_decorator():
    """
    Non-Decorator function that would skip a test if bitsandbytes is missing
    """
    if not is_bnb_available():
        raise SkipTest("Test requires bitsandbytes from https://github.com/facebookresearch/bitsandbytes")


def set_seed(seed: int=42):
    """
    Helper function for reproducible behavior to set the seed in ``random``, ``numpy``, ``torch``

    Args:
        seed (:obj:`int`): The seed to set.
    """
    random.seed(seed)
    np.random.seed(seed)
    if is_torch_available():
        torch.manual_seed(seed)
        torch.cuda.manual_seed_all(seed)
        # ^^ safe to call this function even if cuda is not available

def get_gpu_count():
    """
    Return the number of available gpus (regardless of whether torch or tf is used)
    """
    if is_torch_available():
        import torch

        return torch.cuda.device_count()
    elif is_tf_available():
        import tensorflow as tf

        return len(tf.config.list_physical_devices("GPU"))
    else:
        return 0

def torch_assert_equal(actual, expected, **kwargs):
    # assert_close was added around pt-1.9, it does better checks - e.g will check dimensions match
    if hasattr(torch.testing, "assert_close"):
        return torch.testing.assert_close(actual, expected, rtol=0.0, atol=0.0, **kwargs)
    else:
        return torch.allclose(actual, expected, rtol=0.0, atol=0.0)

def torch_assert_close(actual, expected, **kwargs):
    # assert_close was added around pt-1.9, it does better checks - e.g will check dimensions match
    if hasattr(torch.testing, "assert_close"):
        return torch.testing.assert_close(actual, expected, **kwargs)
    else:
        kwargs.pop("msg", None) # doesn't have msg arg
        return torch.allclose(actual, expected, **kwargs)


def is_torch_bf16_available():
    # from https://github.com/huggingface/transformers/blob/26eb566e43148c80d0ea098c76c3d128c0281c16/src/transformers/file_utils.py#L301
    if is_torch_available():
        import torch
        if not torch.cuda.is_available() or torch.version.cuda is None:
            return False
        if torch.cuda.get_device_properties(torch.cuda.current_device()).major < 8:
            return False
        if int(torch.version.cuda.split(".")[0]) < 11:
            return False
        if not version.parse(torch.__version__) >= version.parse("1.09"):
            return False
        return True
    else:
        return False


def require_torch_bf16(test_case):
    """Decorator marking a test that requires CUDA hardware supporting bf16 and PyTorch >= 1.9."""
    if not is_torch_bf16_available():
        return unittest.skip("test requires CUDA hardware supporting bf16 and PyTorch >= 1.9")(test_case)
    else:
        return test_case


def get_tests_dir(append_path=None):
    """
    Args:
        append_path: optional path to append to the tests dir path

    Return:
        The full path to the `tests` dir, so that the tests can be invoked from anywhere. Optionally `append_path` is
        joined after the `tests` dir the former is provided.

    """
    # this function caller's __file__
    caller__file__ = inspect.stack()[1][1]
    tests_dir = os.path.abspath(os.path.dirname(caller__file__))
    if append_path:
        return os.path.join(tests_dir, append_path)
    else:
        return tests_dir


#
# Helper functions for dealing with testing text outputs
# The original code came from:
# https://github.com/fastai/fastai/blob/master/tests/utils/text.py

# When any function contains print() calls that get overwritten, like progress bars,
# a special care needs to be applied, since under pytest -s captured output (capsys
# or contextlib.redirect_stdout) contains any temporary printed strings, followed by
# \r's. This helper function ensures that the buffer will contain the same output
# with and without -s in pytest, by turning:
# foo bar\r tar mar\r final message
# into:
# final message
# it can handle a single string or a multiline buffer
def apply_print_resets(buf):
    return re.sub(r"^.*\r", "", buf, 0, re.M)


def assert_screenout(out, what):
    out_pr = apply_print_resets(out).lower()
    match_str = out_pr.find(what.lower())
    assert match_str != -1, f"expecting to find {what} in output: f{out_pr}"


class CaptureStd:
    """
    Context manager to capture:

        - stdout: replay it, clean it up and make it available via ``obj.out``
        - stderr: replay it and make it available via ``obj.err``

        init arguments:

        - out - capture stdout:`` True``/``False``, default ``True``
        - err - capture stdout: ``True``/``False``, default ``True``
        - replay - whether to replay or not: ``True``/``False``, default ``True``. By default each
        captured stream gets replayed back on context's exit, so that one can see what the test was
        doing. If this is a not wanted behavior and the captured data shouldn't be replayed, pass
        ``replay=False`` to disable this feature.

        Examples::

            # to capture stdout only with auto-replay
            with CaptureStdout() as cs:
                print("Secret message")
            assert "message" in cs.out

            # to capture stderr only with auto-replay
            import sys
            with CaptureStderr() as cs:
                print("Warning: ", file=sys.stderr)
            assert "Warning" in cs.err

            # to capture both streams with auto-replay
            with CaptureStd() as cs:
                print("Secret message")
                print("Warning: ", file=sys.stderr)
            assert "message" in cs.out
            assert "Warning" in cs.err

            # to capture just one of the streams, and not the other, with auto-replay
            with CaptureStd(err=False) as cs:
                print("Secret message")
            assert "message" in cs.out
            # but best use the stream-specific subclasses

            # to capture without auto-replay
            with CaptureStd(replay=False) as cs:
                print("Secret message")
            assert "message" in cs.out

    """

    def __init__(self, out=True, err=True, replay=True):

        self.replay = replay

        if out:
            self.out_buf = StringIO()
            self.out = "error: CaptureStd context is unfinished yet, called too early"
        else:
            self.out_buf = None
            self.out = "not capturing stdout"

        if err:
            self.err_buf = StringIO()
            self.err = "error: CaptureStd context is unfinished yet, called too early"
        else:
            self.err_buf = None
            self.err = "not capturing stderr"

    def __enter__(self):
        if self.out_buf:
            self.out_old = sys.stdout
            sys.stdout = self.out_buf

        if self.err_buf:
            self.err_old = sys.stderr
            sys.stderr = self.err_buf

        return self

    def __exit__(self, *exc):
        if self.out_buf:
            sys.stdout = self.out_old
            captured = self.out_buf.getvalue()
            if self.replay:
                sys.stdout.write(captured)
            self.out = apply_print_resets(captured)

        if self.err_buf:
            sys.stderr = self.err_old
            captured = self.err_buf.getvalue()
            if self.replay:
                sys.stderr.write(captured)
            self.err = captured

    def __repr__(self):
        msg = ""
        if self.out_buf:
            msg += f"stdout: {self.out}\n"
        if self.err_buf:
            msg += f"stderr: {self.err}\n"
        return msg


# in tests it's the best to capture only the stream that's wanted, otherwise
# it's easy to miss things, so unless you need to capture both streams, use the
# subclasses below (less typing). Or alternatively, configure `CaptureStd` to
# disable the stream you don't need to test.


class CaptureStdout(CaptureStd):
    """Same as CaptureStd but captures only stdout"""

    def __init__(self, replay=True):
        super().__init__(err=False, replay=replay)


class CaptureStderr(CaptureStd):
    """Same as CaptureStd but captures only stderr"""

    def __init__(self, replay=True):
        super().__init__(out=False, replay=replay)


class CaptureLogger:
    """
    Context manager to capture `logging` streams

    Args:

    - logger: 'logging` logger object

    Results:
        The captured output is available via `self.out`

    Example::

        >>> from transformers import logging
        >>> from transformers.testing_utils import CaptureLogger

        >>> msg = "Testing 1, 2, 3"
        >>> logging.set_verbosity_info()
        >>> logger = logging.get_logger("transformers.models.bart.tokenization_bart")
        >>> with CaptureLogger(logger) as cl:
        ...     logger.info(msg)
        >>> assert cl.out, msg+"\n"
    """

    def __init__(self, logger):
        self.logger = logger
        self.io = StringIO()
        self.sh = logging.StreamHandler(self.io)
        self.out = ""

    def __enter__(self):
        self.logger.addHandler(self.sh)
        return self

    def __exit__(self, *exc):
        self.logger.removeHandler(self.sh)
        self.out = self.io.getvalue()

    def __repr__(self):
        return f"captured: {self.out}\n"



@contextlib.contextmanager
# adapted from https://stackoverflow.com/a/64789046/9201239
def ExtendSysPath(path: Union[str, os.PathLike]) -> Iterator[None]:
    """
    Temporary add given path to `sys.path`.

    Usage ::

       with ExtendSysPath('/path/to/dir'):
           mymodule = importlib.import_module('mymodule')

    """

    path = os.fspath(path)
    try:
        sys.path.insert(0, path)
        yield
    finally:
        sys.path.remove(path)


class TestCasePlus(unittest.TestCase):
    """
    This class extends `unittest.TestCase` with additional features.

    Feature 1: A set of fully resolved important file and dir path accessors.

    In tests often we need to know where things are relative to the current test file, and it's not trivial since the
    test could be invoked from more than one directory or could reside in sub-directories with different depths. This
    class solves this problem by sorting out all the basic paths and provides easy accessors to them:

    * ``pathlib`` objects (all fully resolved):

       - ``test_file_path`` - the current test file path (=``__file__``)
       - ``test_file_dir`` - the directory containing the current test file
       - ``tests_dir`` - the directory of the ``tests`` test suite
       - ``data_dir`` - the directory of the ``tests/data`` test suite
       - ``repo_root_dir`` - the directory of the repository
       - ``src_dir`` - the directory of ``src`` (i.e. where the ``transformers`` sub-dir resides)

    * stringified paths---same as above but these return paths as strings, rather than ``pathlib`` objects:

       - ``test_file_path_str``
       - ``test_file_dir_str``
       - ``tests_dir_str``
       - ``data_dir_str``
       - ``repo_root_dir_str``
       - ``src_dir_str``

    Feature 2: Flexible auto-removable temporary dirs which are guaranteed to get removed at the end of test.

    1. Create a unique temporary dir:

    ::

        def test_whatever(self):
            tmp_dir = self.get_auto_remove_tmp_dir()

    ``tmp_dir`` will contain the path to the created temporary dir. It will be automatically removed at the end of the
    test.


    2. Create a temporary dir of my choice, ensure it's empty before the test starts and don't
    empty it after the test.

    ::

        def test_whatever(self):
            tmp_dir = self.get_auto_remove_tmp_dir("./xxx")

    This is useful for debug when you want to monitor a specific directory and want to make sure the previous tests
    didn't leave any data in there.

    3. You can override the first two options by directly overriding the ``before`` and ``after`` args, leading to the
       following behavior:

    ``before=True``: the temporary dir will always be cleared at the beginning of the test.

    ``before=False``: if the temporary dir already existed, any existing files will remain there.

    ``after=True``: the temporary dir will always be deleted at the end of the test.

    ``after=False``: the temporary dir will always be left intact at the end of the test.

    Note 1: In order to run the equivalent of ``rm -r`` safely, only subdirs of the project repository checkout are
    allowed if an explicit ``tmp_dir`` is used, so that by mistake no ``/tmp`` or similar important part of the
    filesystem will get nuked. i.e. please always pass paths that start with ``./``

    Note 2: Each test can register multiple temporary dirs and they all will get auto-removed, unless requested
    otherwise.

    Feature 3: Get a copy of the ``os.environ`` object that sets up ``PYTHONPATH`` specific to the current test suite.
    This is useful for invoking external programs from the test suite - e.g. distributed training.


    ::
        def test_whatever(self):
            env = self.get_env()

    """

    def setUp(self):
        # get_auto_remove_tmp_dir feature:
        self.teardown_tmp_dirs = []

        # figure out the resolved paths for repo_root, tests,  etc.
        self._test_file_path = inspect.getfile(self.__class__)
        path = Path(self._test_file_path).resolve()
        self._test_file_dir = path.parents[0]
        for up in [1, 2, 3]:
            tmp_dir = path.parents[up]
            if (tmp_dir / "megatron").is_dir() and (tmp_dir / "tests").is_dir():
                break
        if tmp_dir:
            self._repo_root_dir = tmp_dir
        else:
            raise ValueError(f"can't figure out the root of the repo from {self._test_file_path}")
        self._tests_dir = self._repo_root_dir / "tests"
        self._data_dir = self._repo_root_dir / "tests" / "data"
        self._src_dir = self._repo_root_dir # megatron doesn't use "src/" prefix in the repo

    @property
    def test_file_path(self):
        return self._test_file_path

    @property
    def test_file_path_str(self):
        return str(self._test_file_path)

    @property
    def test_file_dir(self):
        return self._test_file_dir

    @property
    def test_file_dir_str(self):
        return str(self._test_file_dir)

    @property
    def tests_dir(self):
        return self._tests_dir

    @property
    def tests_dir_str(self):
        return str(self._tests_dir)

    @property
    def data_dir(self):
        return self._data_dir

    @property
    def data_dir_str(self):
        return str(self._data_dir)

    @property
    def repo_root_dir(self):
        return self._repo_root_dir

    @property
    def repo_root_dir_str(self):
        return str(self._repo_root_dir)

    @property
    def src_dir(self):
        return self._src_dir

    @property
    def src_dir_str(self):
        return str(self._src_dir)

    def get_env(self):
        """
        Return a copy of the ``os.environ`` object that sets up ``PYTHONPATH`` correctly. This is useful
        for invoking external programs from the test suite - e.g. distributed training.

        It always inserts ``.`` first, then ``./tests`` depending on the test suite type and
        finally the preset ``PYTHONPATH`` if any (all full resolved paths).

        """
        env = os.environ.copy()
        paths = [self.src_dir_str]
        paths.append(self.tests_dir_str)
        paths.append(env.get("PYTHONPATH", ""))

        env["PYTHONPATH"] = ":".join(paths)
        return env

    def get_auto_remove_tmp_dir(self, tmp_dir=None, before=None, after=None):
        """
        Args:
            tmp_dir (:obj:`string`, `optional`):
                if :obj:`None`:

                   - a unique temporary path will be created
                   - sets ``before=True`` if ``before`` is :obj:`None`
                   - sets ``after=True`` if ``after`` is :obj:`None`
                else:

                   - :obj:`tmp_dir` will be created
                   - sets ``before=True`` if ``before`` is :obj:`None`
                   - sets ``after=False`` if ``after`` is :obj:`None`
            before (:obj:`bool`, `optional`):
                If :obj:`True` and the :obj:`tmp_dir` already exists, make sure to empty it right away if :obj:`False`
                and the :obj:`tmp_dir` already exists, any existing files will remain there.
            after (:obj:`bool`, `optional`):
                If :obj:`True`, delete the :obj:`tmp_dir` at the end of the test if :obj:`False`, leave the
                :obj:`tmp_dir` and its contents intact at the end of the test.

        Returns:
            tmp_dir(:obj:`string`): either the same value as passed via `tmp_dir` or the path to the auto-selected tmp
            dir
        """
        if tmp_dir is not None:

            # defining the most likely desired behavior for when a custom path is provided.
            # this most likely indicates the debug mode where we want an easily locatable dir that:
            # 1. gets cleared out before the test (if it already exists)
            # 2. is left intact after the test
            if before is None:
                before = True
            if after is None:
                after = False

            # using provided path
            path = Path(tmp_dir).resolve()

            # to avoid nuking parts of the filesystem, only relative paths are allowed
            if not tmp_dir.startswith("./"):
                raise ValueError(
                    f"`tmp_dir` can only be a relative path, i.e. `./some/path`, but received `{tmp_dir}`"
                )

            # ensure the dir is empty to start with
            if before is True and path.exists():
                shutil.rmtree(tmp_dir, ignore_errors=True)

            path.mkdir(parents=True, exist_ok=True)

        else:
            # defining the most likely desired behavior for when a unique tmp path is auto generated
            # (not a debug mode), here we require a unique tmp dir that:
            # 1. is empty before the test (it will be empty in this situation anyway)
            # 2. gets fully removed after the test
            if before is None:
                before = True
            if after is None:
                after = True

            # using unique tmp dir (always empty, regardless of `before`)
            tmp_dir = tempfile.mkdtemp()

        if after is True:
            # register for deletion
            self.teardown_tmp_dirs.append(tmp_dir)

        return tmp_dir

    def tearDown(self):

        # get_auto_remove_tmp_dir feature: remove registered temp dirs
        for path in self.teardown_tmp_dirs:
            shutil.rmtree(path, ignore_errors=True)
        self.teardown_tmp_dirs = []


def mockenv(**kwargs):
    """
    this is a convenience wrapper, that allows this ::

    @mockenv(RUN_SLOW=True, USE_TF=False)
    def test_something():
        run_slow = os.getenv("RUN_SLOW", False)
        use_tf = os.getenv("USE_TF", False)

    """
    return mock.patch.dict(os.environ, kwargs)


# from https://stackoverflow.com/a/34333710/9201239
@contextlib.contextmanager
def mockenv_context(*remove, **update):
    """
    Temporarily updates the ``os.environ`` dictionary in-place. Similar to mockenv

    The ``os.environ`` dictionary is updated in-place so that the modification is sure to work in all situations.

    Args:
      remove: Environment variables to remove.
      update: Dictionary of environment variables and values to add/update.
    """
    env = os.environ
    update = update or {}
    remove = remove or []

    # List of environment variables being updated or removed.
    stomped = (set(update.keys()) | set(remove)) & set(env.keys())
    # Environment variables and values to restore on exit.
    update_after = {k: env[k] for k in stomped}
    # Environment variables and values to remove on exit.
    remove_after = frozenset(k for k in update if k not in env)

    try:
        env.update(update)
        [env.pop(k, None) for k in remove]
        yield
    finally:
        env.update(update_after)
        [env.pop(k) for k in remove_after]



# --- distributed testing functions --- #

# adapted from https://stackoverflow.com/a/59041913/9201239
import asyncio  # noqa


class _RunOutput:
    def __init__(self, returncode, stdout, stderr):
        self.returncode = returncode
        self.stdout = stdout
        self.stderr = stderr


async def _read_stream(stream, callback):
    while True:
        line = await stream.readline()
        if line:
            callback(line)
        else:
            break


async def _stream_subprocess(cmd, env=None, stdin=None, timeout=None, quiet=False, echo=False) -> _RunOutput:
    if echo:
        print("\nRunning: ", " ".join(cmd))

    p = await asyncio.create_subprocess_exec(
        cmd[0],
        *cmd[1:],
        stdin=stdin,
        stdout=asyncio.subprocess.PIPE,
        stderr=asyncio.subprocess.PIPE,
        env=env,
    )

    # note: there is a warning for a possible deadlock when using `wait` with huge amounts of data in the pipe
    # https://docs.python.org/3/library/asyncio-subprocess.html#asyncio.asyncio.subprocess.Process.wait
    #
    # If it starts hanging, will need to switch to the following code. The problem is that no data
    # will be seen until it's done and if it hangs for example there will be no debug info.
    # out, err = await p.communicate()
    # return _RunOutput(p.returncode, out, err)

    out = []
    err = []

    def tee(line, sink, pipe, label=""):
        line = line.decode("utf-8").rstrip()
        sink.append(line)
        if not quiet:
            print(label, line, file=pipe)

    # XXX: the timeout doesn't seem to make any difference here
    await asyncio.wait(
        [
            _read_stream(p.stdout, lambda l: tee(l, out, sys.stdout, label="stdout:")),
            _read_stream(p.stderr, lambda l: tee(l, err, sys.stderr, label="stderr:")),
        ],
        timeout=timeout,
    )
    return _RunOutput(await p.wait(), out, err)


def execute_subprocess_async(cmd, env=None, stdin=None, timeout=180, quiet=False, echo=True) -> _RunOutput:

    loop = asyncio.get_event_loop()
    result = loop.run_until_complete(
        _stream_subprocess(cmd, env=env, stdin=stdin, timeout=timeout, quiet=quiet, echo=echo)
    )

    cmd_str = " ".join(cmd)
    if result.returncode > 0:
        stderr = "\n".join(result.stderr)
        raise RuntimeError(
            f"'{cmd_str}' failed with returncode {result.returncode}\n\n"
            f"The combined stderr from workers follows:\n{stderr}"
        )

    # check that the subprocess actually did run and produced some output, should the test rely on
    # the remote side to do the testing
    if not result.stdout and not result.stderr:
        raise RuntimeError(f"'{cmd_str}' produced no output.")

    return result


# --- Misc utils --- #

def flatten_arguments(args):
    """
    Converts dictionary argument to a list.

    Note: we add "IGNORED" at the beginning as this value is ignored by the argparser

    Example: {"arg1": "value1", "arg2": "value2"} -> ["IGNORED", "arg1", "value1", "arg2", "value2"]
    """
    return ["IGNORED"] + [item for key_value in args.items() for item in key_value if item != ""]