iothread is a string property, so None (= JSON null) is not a valid value for it. Pass the empty string instead to get the default iothread. Signed-off-by: Kevin Wolf <kwolf@xxxxxxxxxx> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@xxxxxxxxxxxxx> --- tests/qemu-iotests/245 | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/tests/qemu-iotests/245 b/tests/qemu-iotests/245 index bf8261eec0..9b12b42eed 100755 --- a/tests/qemu-iotests/245 +++ b/tests/qemu-iotests/245 @@ -1189,10 +1189,10 @@ class TestBlockdevReopen(iotests.QMPTestCase): self.run_test_iothreads('iothread0', 'iothread0') def test_iothreads_switch_backing(self): - self.run_test_iothreads('iothread0', None) + self.run_test_iothreads('iothread0', '') def test_iothreads_switch_overlay(self): - self.run_test_iothreads(None, 'iothread0') + self.run_test_iothreads('', 'iothread0') if __name__ == '__main__': iotests.activate_logging() -- 2.31.1