tests: Skip windows.img tests if it is zero-sized.

If ntfs-3g is not installed, then tests/guests creates a 'windows.img'
file which is zero-sized.

This is problematical because other tests which use this image will
fail at best, or hit RHBZ#847549 (qemu/virtio-scsi bug) at worst.

Change the tests which use windows.img so they skip if 'windows.img'
has zero size.

inspector/test-virt-inspector.sh

@@ -20,7 +20,10 @@ export LANG=C
 set -e
 
 for f in ../tests/guests/{debian,fedora,ubuntu,windows}.img; do
-    $VG ./virt-inspector -a $f
+    # Ignore zero-sized windows.img if ntfs-3g is not installed.
+    if [ -s "$f" ]; then
+	$VG ./virt-inspector -a $f
+    fi
 done
 
 # We could also test this image, but mdadm is problematic for

sysprep/test-virt-sysprep.sh

@@ -23,7 +23,10 @@ set -e
 # to be able to sysprep any of our test guests.
 
 for f in ../tests/guests/{debian,fedora,ubuntu,windows}.img; do
-    $VG ./virt-sysprep -q -n -a $f
+    # Ignore zero-sized windows.img if ntfs-3g is not installed.
+    if [ -s "$f" ]; then
+	$VG ./virt-sysprep -q -n -a $f
+    fi
 done
 
 # We could also test this image, but mdadm is problematic for

tests/ntfsclone/test-ntfsclone.sh

@@ -35,6 +35,11 @@ if ! $guestfish add /dev/null : run : available "ntfs3g"; then
     exit 77
 fi
 
+if [ ! -s ../guests/windows.img ]; then
+    echo "$0: skipped because windows.img is zero-sized"
+    exit 77
+fi
+
 # Export the filesystems to the backup file.
 $guestfish --ro -a ../guests/windows.img <<EOF
 run