resize/test-virt-resize.pl: Fix calculation of target disk

We didn't calculate the size of the target disk correctly.  If a
partition is resized then we pass the parameter --resize=(+|-)256M to
virt-resize, but the target disk calculation chose an unrelated value.

Example failure:

seed:           3834767396
partition type: mbr
nr partitions:  3
partition size: 1024M (2097152 sectors)
expand:         0
no extra part:  0
source format:  raw
target format:  raw
filesystem:     ext2
LV expand:
partition 1:    sda1 ext2 resize
partition 2:    sda2 ext2 -
partition 3:    sda3 ext2 shrink
virt-resize --format raw --output-format raw --resize /dev/sda1=-256M --shrink /dev/sda3 test-virt-resize-source.img test-virt-resize-target.img
[   0.0] Examining test-virt-resize-source.img
virt-resize: error: /dev/sda3: This partition contains a ext2 filesystem which will be damaged by shrinking it below 406016000 bytes (user asked to shrink it to 41648128 bytes).  If you want to shrink this partition, you need to use the ‘--resize-force’ option, but that could destroy any data on this partition.  (This error came from ‘--shrink’ option on the command line.)

If reporting bugs, run virt-resize with debugging enabled and include the complete output:

  virt-resize -v -x [...]
command: 'virt-resize --format raw --output-format raw --resize /dev/sda1=-256M --shrink /dev/sda3 test-virt-resize-source.img test-virt-resize-target.img' failed: 256
FAIL test-virt-resize.pl (exit status: 2)

Author: rwmjones

resize/test-virt-resize.pl

@@ -305,7 +305,13 @@
 # will be resized.
 my $target_size = 0;
 for ($i = 1; $i <= $nr_parts; ++$i) {
-    if ($parts[$i]->{resize} || $parts[$i]->{expand_shrink}) {
+    if ($parts[$i]->{resize}) {
+        if ($expand) {
+            $target_size += $part_size_mb + 256;
+        } else {
+            $target_size += $part_size_mb - 256;
+        }
+    } elsif ($parts[$i]->{expand_shrink}) {
         if ($expand) {
             $target_size += $expand_target_size_mb;
         } else {