diff --git a/tests/qemu-iotests/235 b/tests/qemu-iotests/235
index e5d1ae6593..c5264972b9 100755
--- a/tests/qemu-iotests/235
+++ b/tests/qemu-iotests/235
@@ -21,7 +21,7 @@
 import sys
 import os
 import iotests
-from iotests import qemu_img_create, qemu_io, file_path
+from iotests import qemu_img_create, qemu_io, file_path, log
 
 sys.path.append(os.path.join(os.path.dirname(__file__), '..', '..', 'scripts'))
 
@@ -38,22 +38,34 @@ from qemu import QEMUMachine
 #    for me)
 # 4. add iothread
 
-size = '1G'
+size = 1 * 1024 * 1024 * 1024
 
 iotests.verify_image_format(supported_fmts=['raw', 'qcow2'])
 
-disk, target = file_path('disk', 'target')
+disk = file_path('disk')
 
 # prepare source image
-qemu_img_create('-f', iotests.imgfmt, disk, size)
-qemu_io('-f', iotests.imgfmt, '-c', 'write 0 ' + size, disk)
+qemu_img_create('-f', iotests.imgfmt, '-o', 'preallocation=metadata', disk,
+                str(size))
 
 vm = QEMUMachine(iotests.qemu_prog)
 vm.add_args('-machine', 'pc,accel=kvm')
 vm.add_args('-drive', 'id=src,file=' + disk)
 vm.launch()
 
-print(vm.qmp('drive-mirror', device='src', target=target, sync='full'))
+log(vm.qmp('object-add', qom_type='throttle-group', id='tg0',
+           props={ 'x-bps-total': 64 * 1048576 }))
+
+log(vm.qmp('blockdev-add',
+           **{ 'node-name': 'target',
+               'driver': 'throttle',
+               'throttle-group': 'tg0',
+               'file': {
+                   'driver': 'null-co',
+                   'size': size
+                } }))
+
+log(vm.qmp('blockdev-mirror', device='src', target='target', sync='full'))
 vm.event_wait('BLOCK_JOB_READY')
 
 vm.shutdown()
diff --git a/tests/qemu-iotests/235.out b/tests/qemu-iotests/235.out
index d6ccbad8fa..39db621e04 100644
--- a/tests/qemu-iotests/235.out
+++ b/tests/qemu-iotests/235.out
@@ -1 +1,3 @@
-{u'return': {}}
+{"return": {}}
+{"return": {}}
+{"return": {}}