Implement function with du and lstat fallback

In addition, extend the tests for `RemoteData` in `test_remote.py`
for the methods added in this PR, as well as parametrize them to run on
a `RemoteData` via local and ssh transport.

src/aiida/orm/nodes/data/remote/base.py

@@ -10,12 +10,13 @@
 
 from __future__ import annotations
 
-import os
 import logging
+import os
 from pathlib import Path
 
 from aiida.orm import AuthInfo
 from aiida.orm.fields import add_field
+from aiida.transports import Transport
 
 from ..data import Data
 
@@ -109,7 +110,10 @@ def listdir(self, relpath='.'):
             try:
                 return transport.listdir(full_path)
             except OSError as exception:
-                if exception.errno in (2, 20):  # directory not existing or not a directory
+                if exception.errno in (
+                    2,
+                    20,
+                ):  # directory not existing or not a directory
                     exc = OSError(
                         f'The required remote folder {full_path} on {self.computer.label} does not exist, is not a '
                         'directory or has been deleted.'
@@ -138,7 +142,10 @@ def listdir_withattributes(self, path='.'):
             try:
                 return transport.listdir_withattributes(full_path)
             except OSError as exception:
-                if exception.errno in (2, 20):  # directory not existing or not a directory
+                if exception.errno in (
+                    2,
+                    20,
+                ):  # directory not existing or not a directory
                     exc = OSError(
                         f'The required remote folder {full_path} on {self.computer.label} does not exist, is not a '
                         'directory or has been deleted.'
@@ -199,7 +206,8 @@ def get_size_on_disk(self, relpath: Path | None = None) -> str:
         Connects to the remote folder and returns the total size of all files in the directory recursively in a
         human-readable format.
 
-        :param relpath: File or directory path for which the total size should be returned, relative to ``self.get_remote_path``.
+        :param relpath: File or directory path for which the total size should be returned, relative to
+        ``self.get_remote_path``.
         :return: Total size of file or directory in human-readable format.
 
         :raises: FileNotFoundError, if file or directory does not exist.
@@ -213,25 +221,28 @@ def get_size_on_disk(self, relpath: Path | None = None) -> str:
 
         with authinfo.get_transport() as transport:
             if not transport.isdir(str(full_path)) and not transport.isfile(str(full_path)):
-                exc_message = f'The required remote folder {full_path} on Computer <{computer_label}> does not exist, is not a directory or has been deleted.'
+                exc_message = (
+                    f'The required remote folder {full_path} on Computer <{computer_label}>'
+                    'does not exist, is not a directory or has been deleted.'
+                )
                 raise FileNotFoundError(exc_message)
 
             try:
                 total_size: int = self._get_size_on_disk_du(full_path, transport)
 
             except RuntimeError:
-
                 lstat_warn = (
-                    "Problem executing `du` command. Will return total file size based on `lstat`. "
-                    "Take the result with a grain of salt, as `lstat` does not consider the file system block size, "
-                    "but instead returns the true size of the files in bytes, which differs from the actual space requirements on disk."
+                    'Problem executing `du` command. Will return total file size based on `lstat`. '
+                    'Take the result with a grain of salt, as `lstat` does not consider the file system block size, '
+                    'but instead returns the true size of the files in bytes, which differs from the actual space'
+                    'requirements on disk.'
                 )
                 _logger.warning(lstat_warn)
 
                 total_size: int = self._get_size_on_disk_lstat(full_path, transport)
 
             except OSError:
-                _logger.critical("Could not evaluate directory size using either `du` or `lstat`.")
+                _logger.critical('Could not evaluate directory size using either `du` or `lstat`.')
 
         return format_directory_size(size_in_bytes=total_size)
 
@@ -254,13 +265,13 @@ def _get_size_on_disk_du(self, full_path: Path, transport: 'Transport') -> int:
             total_size: int = int(stdout.split('\t')[0])
             return total_size
         else:
-            raise RuntimeError(f"Error executing `du` command: {stderr}")
+            raise RuntimeError(f'Error executing `du` command: {stderr}')
 
     def _get_size_on_disk_lstat(self, full_path, transport) -> int:
-
-        """Connects to the remote folder and returns the total size of all files in the directory recursively in bytes
-        using ``lstat``. Note that even if a file is only 1 byte, on disk, it still occupies one full disk block size. As
-        such, getting accurate measures of the total expected size on disk when retrieving a ``RemoteData`` is not
+        """
+        Connects to the remote folder and returns the total size of all files in the directory recursively in bytes
+        using ``lstat``. Note that even if a file is only 1 byte, on disk, it still occupies one full disk block size.
+        As such, getting accurate measures of the total expected size on disk when retrieving a ``RemoteData`` is not
         straightforward with ``lstat``, as one would need to consider the occupied block sizes for each file, as well as
         repository metadata. Thus, this function only serves as a fallback in the absence of the ``du`` command.
 

tests/orm/nodes/data/test_remote.py

@@ -23,6 +23,7 @@ def remote_data_local(tmp_path, aiida_localhost):
     (tmp_path / 'file.txt').write_bytes(b'some content')
     return node
 
+
 @pytest.fixture
 def remote_data_ssh(tmp_path, aiida_computer_ssh):
     """Return a non-empty ``RemoteData`` instance."""
@@ -35,7 +36,8 @@ def remote_data_ssh(tmp_path, aiida_computer_ssh):
     (tmp_path / 'file.txt').write_bytes(b'some content')
     return node
 
-@pytest.mark.parametrize('fixture', ["remote_data_local", "remote_data_ssh"])
+
+@pytest.mark.parametrize('fixture', ['remote_data_local', 'remote_data_ssh'])
 def test_clean(request, fixture):
     """Test the :meth:`aiida.orm.nodes.data.remote.base.RemoteData.clean` method."""
 
@@ -47,7 +49,8 @@ def test_clean(request, fixture):
     assert remote_data.is_empty
     assert remote_data.is_cleaned
 
-@pytest.mark.parametrize('fixture', ["remote_data_local", "remote_data_ssh"])
+
+@pytest.mark.parametrize('fixture', ['remote_data_local', 'remote_data_ssh'])
 def test_get_size_on_disk_du(request, fixture, monkeypatch):
     """Test the :meth:`aiida.orm.nodes.data.remote.base.RemoteData.clean` method."""
 
@@ -66,11 +69,11 @@ def mock_exec_command_wait(command):
         return (1, '', 'Error executing `du` command')
 
     monkeypatch.setattr(transport, 'exec_command_wait', mock_exec_command_wait)
-    with pytest.raises(RuntimeError) as excinfo:
+    with pytest.raises(RuntimeError, match='Error executing `du`.*'):
         remote_data._get_size_on_disk_du(full_path, transport)
 
 
-@pytest.mark.parametrize('fixture', ["remote_data_local", "remote_data_ssh"])
+@pytest.mark.parametrize('fixture', ['remote_data_local', 'remote_data_ssh'])
 def test_get_size_on_disk_lstat(request, fixture):
     """Test the :meth:`aiida.orm.nodes.data.remote.base.RemoteData.clean` method."""
 
@@ -84,13 +87,14 @@ def test_get_size_on_disk_lstat(request, fixture):
     assert size_on_disk == 12
 
 
-@pytest.mark.parametrize('fixture', ["remote_data_local", "remote_data_ssh"])
+@pytest.mark.parametrize('fixture', ['remote_data_local', 'remote_data_ssh'])
 def test_get_size_on_disk(request, fixture):
     """Test the :meth:`aiida.orm.nodes.data.remote.base.RemoteData.clean` method."""
 
     remote_data = request.getfixturevalue(fixture)
 
-    # Check here for human-readable output string, as integer byte values are checked in `test_get_size_on_disk_[du|lstat]`
+    # Check here for human-readable output string, as integer byte values are checked in
+    # `test_get_size_on_disk_[du|lstat]`
     size_on_disk = remote_data.get_size_on_disk()
     assert size_on_disk == '4.01 KB'