diff --git a/tools/testing/kunit/kunit_tool_test.py b/tools/testing/kunit/kunit_tool_test.py
index 4a12baa0cd4e0d6cd38b3a954a736ece3be32fc9..a2a8ea6beae34509aa7c08bb95ba71aef3b6c027 100755
--- a/tools/testing/kunit/kunit_tool_test.py
+++ b/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(timeout=timeout)
+		self.linux_source_mock.run_kernel.assert_called_once_with(build_dir=None, timeout=timeout)
 		self.print_mock.assert_any_call(StrContains('Testing complete.'))
 
 if __name__ == '__main__':