iotests/283: Use consistent size for source and target

The test case forgot to specify the null-co size for the target node.
When adding a check to backup that both sizes match, this would fail
because of the size mismatch and not the behaviour that the test really
wanted to test.

Fixes: a541fcc27c98b96da187c7d4573f3270f3ddd283
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20200430142755.315494-2-kwolf@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
(cherry picked from commit 813cc2545b82409fd504509f0ba2e96fab6edb9e)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
diff --git a/tests/qemu-iotests/283 b/tests/qemu-iotests/283
index 293e557..a82e3c8 100644
--- a/tests/qemu-iotests/283
+++ b/tests/qemu-iotests/283
@@ -72,7 +72,11 @@
 vm = iotests.VM()
 vm.launch()
 
-vm.qmp_log('blockdev-add', **{'node-name': 'target', 'driver': 'null-co'})
+vm.qmp_log('blockdev-add', **{
+    'node-name': 'target',
+    'driver': 'null-co',
+    'size': size,
+})
 
 vm.qmp_log('blockdev-add', **{
     'node-name': 'source',
diff --git a/tests/qemu-iotests/283.out b/tests/qemu-iotests/283.out
index daaf582..d8cff22 100644
--- a/tests/qemu-iotests/283.out
+++ b/tests/qemu-iotests/283.out
@@ -1,4 +1,4 @@
-{"execute": "blockdev-add", "arguments": {"driver": "null-co", "node-name": "target"}}
+{"execute": "blockdev-add", "arguments": {"driver": "null-co", "node-name": "target", "size": 1048576}}
 {"return": {}}
 {"execute": "blockdev-add", "arguments": {"driver": "blkdebug", "image": {"driver": "null-co", "node-name": "base", "size": 1048576}, "node-name": "source"}}
 {"return": {}}