kunit: add run_checks.py script to validate kunit changes

This formalizes the checks KUnit maintainers have been running (or in
other cases: forgetting to run).

This script also runs them all in parallel to minimize friction (pytype
can be fairly slow, but not slower than running kunit.py).

Example output:
$ ./tools/testing/kunit/run_checks.py
Waiting on 4 checks (kunit_tool_test.py, kunit smoke test, pytype, mypy)...
kunit_tool_test.py: PASSED
mypy: PASSED
pytype: PASSED
kunit smoke test: PASSED

On failure or timeout (5 minutes), it'll dump out the stdout/stderr.
E.g. adding in a type-checking error:
  mypy: FAILED
  > kunit.py:54: error: Name 'nonexistent_function' is not defined
  > Found 1 error in 1 file (checked 8 source files)

mypy and pytype are two Python type-checkers and must be installed.
This file treats them as optional and will mark them as SKIPPED if not
installed.

This tool also runs `kunit.py run --kunitconfig=lib/kunit` to run
KUnit's own KUnit tests and to verify KUnit kernel code and kunit.py
play nicely together.

It uses --build_dir=kunit_run_checks so as not to clobber the default
build_dir, which helps make it faster by reducing the need to rebuild,
esp. if you're been passing in --arch instead of using UML.
Signed-off-by: Daniel Latypov <dlatypov@google.com>
Reviewed-by: David Gow <davidgow@google.com>
Reviewed-by: David Gow <davidgow@google.com>
Reviewed-by: Brendan Higgins <brendanhiggins@google.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

tools/testing/kunit/run_checks.py

+#!/usr/bin/env python3
+# SPDX-License-Identifier: GPL-2.0
+#
+# This file runs some basic checks to verify kunit works.
+# It is only of interest if you're making changes to KUnit itself.
+#
+# Copyright (C) 2021, Google LLC.
+# Author: Daniel Latypov <dlatypov@google.com.com>
+
+from concurrent import futures
+import datetime
+import os
+import shutil
+import subprocess
+import sys
+import textwrap
+from typing import Dict, List, Sequence, Tuple
+
+ABS_TOOL_PATH = os.path.abspath(os.path.dirname(__file__))
+TIMEOUT = datetime.timedelta(minutes=5).total_seconds()
+
+commands: Dict[str, Sequence[str]] = {
+	'kunit_tool_test.py': ['./kunit_tool_test.py'],
+	'kunit smoke test': ['./kunit.py', 'run', '--kunitconfig=lib/kunit', '--build_dir=kunit_run_checks'],
+	'pytype': ['/bin/sh', '-c', 'pytype *.py'],
+	'mypy': ['/bin/sh', '-c', 'mypy *.py'],
+}
+
+# The user might not have mypy or pytype installed, skip them if so.
+# Note: you can install both via `$ pip install mypy pytype`
+necessary_deps : Dict[str, str] = {
+	'pytype': 'pytype',
+	'mypy': 'mypy',
+}
+
+def main(argv: Sequence[str]) -> None:
+	if argv:
+		raise RuntimeError('This script takes no arguments')
+
+	future_to_name: Dict[futures.Future, str] = {}
+	executor = futures.ThreadPoolExecutor(max_workers=len(commands))
+	for name, argv in commands.items():
+		if name in necessary_deps and shutil.which(necessary_deps[name]) is None:
+			print(f'{name}: SKIPPED, {necessary_deps[name]} not in $PATH')
+			continue
+		f = executor.submit(run_cmd, argv)
+		future_to_name[f] = name
+
+	has_failures = False
+	print(f'Waiting on {len(future_to_name)} checks ({", ".join(future_to_name.values())})...')
+	for f in  futures.as_completed(future_to_name.keys()):
+		name = future_to_name[f]
+		ex = f.exception()
+		if not ex:
+			print(f'{name}: PASSED')
+			continue
+
+		has_failures = True
+		if isinstance(ex, subprocess.TimeoutExpired):
+			print(f'{name}: TIMED OUT')
+		elif isinstance(ex, subprocess.CalledProcessError):
+			print(f'{name}: FAILED')
+		else:
+			print('{name}: unexpected exception: {ex}')
+			continue
+
+		output = ex.output
+		if output:
+			print(textwrap.indent(output.decode(), '> '))
+	executor.shutdown()
+
+	if has_failures:
+		sys.exit(1)
+
+
+def run_cmd(argv: Sequence[str]):
+	subprocess.check_output(argv, stderr=subprocess.STDOUT, cwd=ABS_TOOL_PATH, timeout=TIMEOUT)
+
+
+if __name__ == '__main__':
+	main(sys.argv[1:])