kunit: tool: misc cleanups

This primarily comes from running pylint over kunit tool code and
ignoring some warnings we don't care about.
If we ever got a fully clean setup, we could add this to run_checks.py,
but we're not there yet.

Fix things like
* Drop unused imports
* check `is None`, not `== None` (see PEP 8)
* remove redundant parens around returns
* remove redundant `else` / convert `elif` to `if` where appropriate
* rename make_arch_qemuconfig() param to base_kunitconfig (this is the
name used in the subclass, and it's a better one)
* kunit_tool_test: check the exit code for SystemExit (could be 0)

Signed-off-by: Daniel Latypov <[e-mail]>
Reviewed-by: David Gow <[e-mail]>
Reviewed-by: Brendan Higgins <[e-mail]>
Signed-off-by: Shuah Khan <[e-mail]>

tools/testing/kunit/kunit.py

···
 	lines.pop()
 
 	# Filter out any extraneous non-test output that might have gotten mixed in.
-	return [l for l in lines if re.match('^[^\s.]+\.[^\s.]+$', l)]
+	return [l for l in lines if re.match(r'^[^\s.]+\.[^\s.]+$', l)]
 
 def _suites_from_test_list(tests: List[str]) -> List[str]:
 	"""Extracts all the suites from an ordered list of tests."""
···
 def _map_to_overall_status(test_status: kunit_parser.TestStatus) -> KunitStatus:
 	if test_status in (kunit_parser.TestStatus.SUCCESS, kunit_parser.TestStatus.SKIPPED):
 		return KunitStatus.SUCCESS
-	else:
-		return KunitStatus.TEST_FAILURE
+	return KunitStatus.TEST_FAILURE
 
 def parse_tests(request: KunitParseRequest, metadata: kunit_json.Metadata, input_data: Iterable[str]) -> Tuple[KunitResult, kunit_parser.Test]:
 	parse_start = time.time()
···
 			    'a non-hermetic test, one that might pass/fail based on '
 			    'what ran before it.',
 			    type=str,
-			    choices=['suite', 'test']),
+			    choices=['suite', 'test'])
 
 def add_parse_opts(parser) -> None:
 	parser.add_argument('--raw_output', help='If set don\'t format output from kernel. '
···
 		if result.status != KunitStatus.SUCCESS:
 			sys.exit(1)
 	elif cli_args.subcommand == 'parse':
-		if cli_args.file == None:
+		if cli_args.file is None:
 			sys.stdin.reconfigure(errors='backslashreplace')  # pytype: disable=attribute-error
 			kunit_output = sys.stdin
 		else:

tools/testing/kunit/kunit_config.py

···
 
 	def __str__(self) -> str:
 		if self.value == 'n':
-			return r'# CONFIG_%s is not set' % (self.name)
-		else:
-			return r'CONFIG_%s=%s' % (self.name, self.value)
+			return f'# CONFIG_{self.name} is not set'
+		return f'CONFIG_{self.name}={self.value}'
 
 
 class KconfigParseError(Exception):
 	"""Error parsing Kconfig defconfig or .config."""
 
 
-class Kconfig(object):
+class Kconfig:
 	"""Represents defconfig or .config specified using the Kconfig language."""
 
 	def __init__(self) -> None:
···
 				if a.value == 'n':
 					continue
 				return False
-			elif a.value != b:
+			if a.value != b:
 				return False
 		return True
 
···
 
 		if line[0] == '#':
 			continue
-		else:
-			raise KconfigParseError('Failed to parse: ' + line)
+		raise KconfigParseError('Failed to parse: ' + line)
 	return kconfig

tools/testing/kunit/kunit_json.py

···
 
 from dataclasses import dataclass
 import json
-import os
-
-import kunit_parser
+from typing import Any, Dict
 
 from kunit_parser import Test, TestStatus
-from typing import Any, Dict
 
 @dataclass
 class Metadata:

tools/testing/kunit/kunit_kernel.py

···
 	"""Represents an error trying to build the Linux kernel."""
 
 
-class LinuxSourceTreeOperations(object):
+class LinuxSourceTreeOperations:
 	"""An abstraction over command line operations performed on a source tree."""
 
 	def __init__(self, linux_arch: str, cross_compile: Optional[str]):
···
 		except subprocess.CalledProcessError as e:
 			raise ConfigError(e.output.decode())
 
-	def make_arch_qemuconfig(self, kconfig: kunit_config.Kconfig) -> None:
+	def make_arch_qemuconfig(self, base_kunitconfig: kunit_config.Kconfig) -> None:
 		pass
 
 	def make_allyesconfig(self, build_dir: str, make_options) -> None:
···
 	config_path = os.path.join(QEMU_CONFIGS_DIR, arch + '.py')
 	if arch == 'um':
 		return LinuxSourceTreeOperationsUml(cross_compile=cross_compile)
-	elif os.path.isfile(config_path):
+	if os.path.isfile(config_path):
 		return get_source_tree_ops_from_qemu_config(config_path, cross_compile)[1]
 
 	options = [f[:-3] for f in os.listdir(QEMU_CONFIGS_DIR) if f.endswith('.py')]
···
 	return params.linux_arch, LinuxSourceTreeOperationsQemu(
 			params, cross_compile=cross_compile)
 
-class LinuxSourceTree(object):
+class LinuxSourceTree:
 	"""Represents a Linux kernel source tree with KUnit tests."""
 
 	def __init__(
···
 			waiter.join()
 			subprocess.call(['stty', 'sane'])
 
-	def signal_handler(self, sig, frame) -> None:
+	def signal_handler(self, unused_sig, unused_frame) -> None:
 		logging.error('Build interruption occurred. Cleaning console.')
 		subprocess.call(['stty', 'sane'])

tools/testing/kunit/kunit_parser.py

···
 
 import datetime
 from enum import Enum, auto
-from functools import reduce
 from typing import Iterable, Iterator, List, Optional, Tuple
 
-class Test(object):
+class Test:
 	"""
 	A class to represent a test parsed from KTAP results. All KTAP
 	results within a test log are stored in a main Test object as
···
 		"""
 		if self.total() == 0:
 			return TestStatus.NO_TESTS
-		elif self.crashed:
+		if self.crashed:
 			# Crashes should take priority.
 			return TestStatus.TEST_CRASHED
-		elif self.failed:
+		if self.failed:
 			return TestStatus.FAILURE
-		elif self.passed:
+		if self.passed:
 			# No failures or crashes, looks good!
 			return TestStatus.SUCCESS
-		else:
-			# We have only skipped tests.
-			return TestStatus.SKIPPED
+		# We have only skipped tests.
+		return TestStatus.SKIPPED
 
 	def add_status(self, status: TestStatus) -> None:
 		"""Increments the count for `status`."""
···
 	if not match:
 		return False
 	name = match.group(4)
-	return (name == test.name)
+	return name == test.name
 
 def parse_test_result(lines: LineStream, test: Test,
 			expected_num: int) -> bool:
···
 	String containing formatted test result
 	"""
 	if test.status == TestStatus.SUCCESS:
-		return (green('[PASSED] ') + test.name)
-	elif test.status == TestStatus.SKIPPED:
-		return (yellow('[SKIPPED] ') + test.name)
-	elif test.status == TestStatus.NO_TESTS:
-		return (yellow('[NO TESTS RUN] ') + test.name)
-	elif test.status == TestStatus.TEST_CRASHED:
+		return green('[PASSED] ') + test.name
+	if test.status == TestStatus.SKIPPED:
+		return yellow('[SKIPPED] ') + test.name
+	if test.status == TestStatus.NO_TESTS:
+		return yellow('[NO TESTS RUN] ') + test.name
+	if test.status == TestStatus.TEST_CRASHED:
 		print_log(test.log)
-		return (red('[CRASHED] ') + test.name)
-	else:
-		print_log(test.log)
-		return (red('[FAILED] ') + test.name)
+		return red('[CRASHED] ') + test.name
+	print_log(test.log)
+	return red('[FAILED] ') + test.name
 
 def print_test_result(test: Test) -> None:
 	"""
···
 	"""
 	if test.status == TestStatus.SUCCESS:
 		color = green
-	elif test.status == TestStatus.SKIPPED or test.status == TestStatus.NO_TESTS:
+	elif test.status in (TestStatus.SKIPPED, TestStatus.NO_TESTS):
 		color = yellow
 	else:
 		color = red

tools/testing/kunit/kunit_tool_test.py

···
 
 	def test_ignores_hyphen(self):
 		hyphen_log = test_data_path('test_strip_hyphen.log')
-		file = open(hyphen_log)
-		result = kunit_parser.parse_run_tests(file.readlines())
+		with open(hyphen_log) as file:
+			result = kunit_parser.parse_run_tests(file.readlines())
 
 		# A skipped test does not fail the whole suite.
 		self.assertEqual(
···
 		called_times = 0
 		def generator():
 			nonlocal called_times
-			for i in range(1,5):
+			for _ in range(1,5):
 				called_times += 1
 				yield called_times, str(called_times)
 
···
 	def test_exec_no_tests(self):
 		self.linux_source_mock.run_kernel = mock.Mock(return_value=['TAP version 14', '1..0'])
 		with self.assertRaises(SystemExit) as e:
-		  kunit.main(['run'], self.linux_source_mock)
+			kunit.main(['run'], self.linux_source_mock)
+		self.assertEqual(e.exception.code, 1)
 		self.linux_source_mock.run_kernel.assert_called_once_with(
 			args=None, build_dir='.kunit', filter_glob='', timeout=300)
 		self.print_mock.assert_any_call(StrContains(' 0 tests run!'))
···
 		self.linux_source_mock.run_kernel = mock.Mock(return_value=[])
 		with self.assertRaises(SystemExit) as e:
 			kunit.main(['run', '--raw_output=invalid'], self.linux_source_mock)
+		self.assertNotEqual(e.exception.code, 0)
 
 	def test_run_raw_output_does_not_take_positional_args(self):
 		# --raw_output is a string flag, but we don't want it to consume

tools/testing/kunit/run_checks.py

···
 import subprocess
 import sys
 import textwrap
-from typing import Dict, List, Sequence, Tuple
+from typing import Dict, List, Sequence
 
 ABS_TOOL_PATH = os.path.abspath(os.path.dirname(__file__))
 TIMEOUT = datetime.timedelta(minutes=5).total_seconds()