iotests: split linters.py out from 297

Now, 297 is just the iotests-specific incantations and linters.py is as
minimal as I can think to make it. The only remaining element in here
that ought to be configuration and not code is the list of skip files,
but they're still numerous enough that repeating them for mypy and
pylint configurations both would be ... a hassle.

Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Hanna Reitz <hreitz@redhat.com>
Message-id: 20211019144918.3159078-12-jsnow@redhat.com
Signed-off-by: John Snow <jsnow@redhat.com>

tests/qemu-iotests/linters.py

@@ -0,0 +1,76 @@
+# Copyright (C) 2020 Red Hat, Inc.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+import os
+import re
+import subprocess
+from typing import List, Mapping, Optional
+
+
+# TODO: Empty this list!
+SKIP_FILES = (
+    '030', '040', '041', '044', '045', '055', '056', '057', '065', '093',
+    '096', '118', '124', '132', '136', '139', '147', '148', '149',
+    '151', '152', '155', '163', '165', '194', '196', '202',
+    '203', '205', '206', '207', '208', '210', '211', '212', '213', '216',
+    '218', '219', '224', '228', '234', '235', '236', '237', '238',
+    '240', '242', '245', '246', '248', '255', '256', '257', '258', '260',
+    '262', '264', '266', '274', '277', '280', '281', '295', '296', '298',
+    '299', '302', '303', '304', '307',
+    'nbd-fault-injector.py', 'qcow2.py', 'qcow2_format.py', 'qed.py'
+)
+
+
+def is_python_file(filename):
+    if not os.path.isfile(filename):
+        return False
+
+    if filename.endswith('.py'):
+        return True
+
+    with open(filename, encoding='utf-8') as f:
+        try:
+            first_line = f.readline()
+            return re.match('^#!.*python', first_line) is not None
+        except UnicodeDecodeError:  # Ignore binary files
+            return False
+
+
+def get_test_files() -> List[str]:
+    named_tests = [f'tests/{entry}' for entry in os.listdir('tests')]
+    check_tests = set(os.listdir('.') + named_tests) - set(SKIP_FILES)
+    return list(filter(is_python_file, check_tests))
+
+
+def run_linter(
+        tool: str,
+        args: List[str],
+        env: Optional[Mapping[str, str]] = None,
+        suppress_output: bool = False,
+) -> None:
+    """
+    Run a python-based linting tool.
+
+    :param suppress_output: If True, suppress all stdout/stderr output.
+    :raise CalledProcessError: If the linter process exits with failure.
+    """
+    subprocess.run(
+        ('python3', '-m', tool, *args),
+        env=env,
+        check=True,
+        stdout=subprocess.PIPE if suppress_output else None,
+        stderr=subprocess.STDOUT if suppress_output else None,
+        universal_newlines=True,
+    )