iotests/backup-discard-source: convert size variable to be int

Make variable reusable in code for checks. Don't care to change "512 *
1024" invocations as they will be dropped in the next commit.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
Message-ID: <20240620144402.65896-2-vsementsov@yandex-team.ru>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

tests/qemu-iotests/tests/backup-discard-source

@@ -28,7 +28,7 @@ from iotests import qemu_img_create, qemu_img_map, qemu_io
 temp_img = os.path.join(iotests.test_dir, 'temp')
 source_img = os.path.join(iotests.test_dir, 'source')
 target_img = os.path.join(iotests.test_dir, 'target')
-size = '1M'
+size = 1024 * 1024
 
 
 def get_actual_size(vm, node_name):
@@ -39,9 +39,9 @@ def get_actual_size(vm, node_name):
 
 class TestBackup(iotests.QMPTestCase):
     def setUp(self):
-        qemu_img_create('-f', iotests.imgfmt, source_img, size)
-        qemu_img_create('-f', iotests.imgfmt, temp_img, size)
-        qemu_img_create('-f', iotests.imgfmt, target_img, size)
+        qemu_img_create('-f', iotests.imgfmt, source_img, str(size))
+        qemu_img_create('-f', iotests.imgfmt, temp_img, str(size))
+        qemu_img_create('-f', iotests.imgfmt, target_img, str(size))
         qemu_io('-c', 'write 0 1M', source_img)
 
         self.vm = iotests.VM()
@@ -98,7 +98,7 @@ class TestBackup(iotests.QMPTestCase):
         mapping = qemu_img_map(temp_img)
         self.assertEqual(len(mapping), 1)
         self.assertEqual(mapping[0]['start'], 0)
-        self.assertEqual(mapping[0]['length'], 1024 * 1024)
+        self.assertEqual(mapping[0]['length'], size)
         self.assertEqual(mapping[0]['data'], False)
 
         os.remove(temp_img)
@@ -125,7 +125,7 @@ class TestBackup(iotests.QMPTestCase):
         self.assert_qmp(result, 'return', '')
 
         # Check that data is written to temporary image
-        self.assertGreater(get_actual_size(self.vm, 'temp'), 1024 * 1024)
+        self.assertGreater(get_actual_size(self.vm, 'temp'), size)
 
         self.do_backup()