kunit: defconfig: add defconfigs for building KUnit tests

Add defconfig for UML and a fragment that can be used to configure other
architectures for building KUnit tests. Add option to kunit_tool to use
a defconfig to create the kunitconfig.
Signed-off-by: Brendan Higgins <brendanhiggins@google.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Logan Gunthorpe <logang@deltatee.com>
Reviewed-by: Stephen Boyd <sboyd@kernel.org>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

arch/um/configs/kunit_defconfig

+CONFIG_KUNIT=y
+CONFIG_KUNIT_TEST=y
+CONFIG_KUNIT_EXAMPLE_TEST=y

tools/testing/kunit/configs/all_tests.config

+CONFIG_KUNIT=y
+CONFIG_KUNIT_TEST=y
+CONFIG_KUNIT_EXAMPLE_TEST=y

tools/testing/kunit/kunit.py

@@ -11,6 +11,7 @@ import argparse
 import sys
 import os
 import time
+import shutil
 
 from collections import namedtuple
 from enum import Enum, auto
@@ -21,7 +22,7 @@ import kunit_parser
 
 KunitResult = namedtuple('KunitResult', ['status','result'])
 
-KunitRequest = namedtuple('KunitRequest', ['raw_output','timeout', 'jobs', 'build_dir'])
+KunitRequest = namedtuple('KunitRequest', ['raw_output','timeout', 'jobs', 'build_dir', 'defconfig'])
 
 class KunitStatus(Enum):
 	SUCCESS = auto()
@@ -29,8 +30,16 @@ class KunitStatus(Enum):
 	BUILD_FAILURE = auto()
 	TEST_FAILURE = auto()
 
+def create_default_kunitconfig():
+	if not os.path.exists(kunit_kernel.KUNITCONFIG_PATH):
+		shutil.copyfile('arch/um/configs/kunit_defconfig',
+				kunit_kernel.KUNITCONFIG_PATH)
+
 def run_tests(linux: kunit_kernel.LinuxSourceTree,
 	      request: KunitRequest) -> KunitResult:
+	if request.defconfig:
+		create_default_kunitconfig()
+
 	config_start = time.time()
 	success = linux.build_reconfig(request.build_dir)
 	config_end = time.time()
@@ -72,7 +81,7 @@ def run_tests(linux: kunit_kernel.LinuxSourceTree,
 	else:
 		return KunitResult(KunitStatus.SUCCESS, test_result)
 
-def main(argv, linux):
+def main(argv, linux=None):
 	parser = argparse.ArgumentParser(
 			description='Helps writing and running KUnit tests.')
 	subparser = parser.add_subparsers(dest='subcommand')
@@ -99,13 +108,24 @@ def main(argv, linux):
 				'directory.',
 				type=str, default=None, metavar='build_dir')
 
+	run_parser.add_argument('--defconfig',
+				help='Uses a default kunitconfig.',
+				action='store_true')
+
 	cli_args = parser.parse_args(argv)
 
 	if cli_args.subcommand == 'run':
+		if cli_args.defconfig:
+			create_default_kunitconfig()
+
+		if not linux:
+			linux = kunit_kernel.LinuxSourceTree()
+
 		request = KunitRequest(cli_args.raw_output,
 				       cli_args.timeout,
 				       cli_args.jobs,
-				       cli_args.build_dir)
+				       cli_args.build_dir,
+				       cli_args.defconfig)
 		result = run_tests(linux, request)
 		if result.status != KunitStatus.SUCCESS:
 			sys.exit(1)
@@ -113,4 +133,4 @@ def main(argv, linux):
 		parser.print_help()
 
 if __name__ == '__main__':
-	main(sys.argv[1:], kunit_kernel.LinuxSourceTree())
+	main(sys.argv[1:])

tools/testing/kunit/kunit_kernel.py

@@ -14,6 +14,7 @@ import os
 import kunit_config
 
 KCONFIG_PATH = '.config'
+KUNITCONFIG_PATH = 'kunitconfig'
 
 class ConfigError(Exception):
 	"""Represents an error trying to configure the Linux kernel."""
@@ -81,7 +82,7 @@ class LinuxSourceTree(object):
 
 	def __init__(self):
 		self._kconfig = kunit_config.Kconfig()
-		self._kconfig.read_from_file('kunitconfig')
+		self._kconfig.read_from_file(KUNITCONFIG_PATH)
 		self._ops = LinuxSourceTreeOperations()
 
 	def clean(self):