kunit: Place 'test.log' under the 'build_dir'

'kunit' writes the 'test.log' under the kernel source directory even
though a 'build_dir' option is given.  As users who use the option might
expect the outputs to be placed under the specified directory, this
commit modifies the logic to write the log file under the 'build_dir'.
Signed-off-by: SeongJae Park <sjpark@amazon.de>
Reviewed-by: Brendan Higgins <brendanhiggins@google.com>
Tested-by: Brendan Higgins <brendanhiggins@google.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

tools/testing/kunit/kunit.py

@@ -105,7 +105,7 @@ def main(argv, linux=None):
 	run_parser.add_argument('--build_dir',
 				help='As in the make command, it specifies the build '
 				'directory.',
-				type=str, default=None, metavar='build_dir')
+				type=str, default='', metavar='build_dir')
 
 	run_parser.add_argument('--defconfig',
 				help='Uses a default kunitconfig.',

tools/testing/kunit/kunit_kernel.py

@@ -140,10 +140,10 @@ class LinuxSourceTree(object):
 			return False
 		return True
 
-	def run_kernel(self, args=[], timeout=None, build_dir=None):
+	def run_kernel(self, args=[], timeout=None, build_dir=''):
 		args.extend(['mem=256M'])
 		process = self._ops.linux_bin(args, timeout, build_dir)
-		with open('test.log', 'w') as f:
+		with open(os.path.join(build_dir, 'test.log'), 'w') as f:
 			for line in process.stdout:
 				f.write(line.rstrip().decode('ascii') + '\n')
 				yield line.rstrip().decode('ascii')

tools/testing/kunit/kunit_tool_test.py

@@ -199,7 +199,7 @@ class KUnitMainTest(unittest.TestCase):
 		timeout = 3453
 		kunit.main(['run', '--timeout', str(timeout)], self.linux_source_mock)
 		assert self.linux_source_mock.build_reconfig.call_count == 1
-		self.linux_source_mock.run_kernel.assert_called_once_with(build_dir=None, timeout=timeout)
+		self.linux_source_mock.run_kernel.assert_called_once_with(build_dir='', timeout=timeout)
 		self.print_mock.assert_any_call(StrContains('Testing complete.'))
 
 if __name__ == '__main__':