diff --git a/test b/test
index 1792e1d..76d410f 100755
--- a/test
+++ b/test
@@ -138,6 +138,10 @@ check() {
       grep -s "active $1 " /proc/mdstat > /dev/null || {
 		echo >&2 "ERROR active $1 not found" ; cat /proc/mdstat ; exit 1;}
      ;;
+    algorithm )
+      grep -s " algorithm $2 " /proc/mdstat > /dev/null || {
+	  echo >&2 "ERROR algorithm $2 not found"; cat /proc/mdstat; exit 1;}
+     ;;
     resync | recovery | reshape)
       sleep 0.5
       grep -s $1 /proc/mdstat > /dev/null || {
diff --git a/tests/05r6tor0 b/tests/05r6tor0
new file mode 100644
index 0000000..a22b216
--- /dev/null
+++ b/tests/05r6tor0
@@ -0,0 +1,22 @@
+set -x -e
+
+# reshape a RAID6 to RAID5 and then RAID0.
+# then reshape back up to RAID5 and RAID5
+
+mdadm -CR $md0 -l6 -n5 $dev0 $dev1 $dev2 $dev3 $dev4
+check wait
+check raid6
+mdadm -G $md0 -l5
+check wait
+check raid5
+mdadm -G $md0 -l0
+check wait
+check raid0
+mdadm -G $md0 -l5 --add $dev3 $dev4
+check wait
+check raid5
+check algorithm 2
+mdadm -G $md0 -l 6
+check wait
+check raid6
+check algorithm 2