vmcheck: strengthen test harness

We now make the test harness handle restoring the VM to the original
state. The wonderful thing about ostree here is that it's a perfect
shoo-in for this. We make a 'backup' of the current ref, and just have
to make sure that the VM is back on that ref after running each test.

This will allow us to write tests without worrying as much about
cleaning up in the event of an error.

Closes: #360
Approved by: cgwalters

tests/common/libvm.sh

@@ -74,15 +74,34 @@ vm_has_packages() {
   done
 }
 
+# retrieve info from the booted deployment
+# - $1   key to retrieve
+vm_get_booted_deployment_info() {
+  key=$1
+  vm_cmd rpm-ostree status --json | \
+    python -c "
+import sys, json
+deployments = json.load(sys.stdin)[\"deployments\"]
+booted = None
+for deployment in deployments:
+  if deployment[\"booted\"]:
+    booted = deployment
+    break
+if not booted:
+  print \"Failed to determine currently booted deployment\"
+  exit(1)
+if \"$key\" in booted:
+  data = booted[\"$key\"]
+  if type(data) is list:
+    print \" \".join(data)
+  else:
+    print data
+"
+}
+
 # print the layered packages
 vm_get_layered_packages() {
-  vm_cmd rpm-ostree status --json | \
-    python -c '
-import sys, json
-depl = json.load(sys.stdin)["deployments"][0]
-if "packages" in depl:
-  print " ".join(depl["packages"])
-'
+  vm_get_booted_deployment_info packages
 }
 
 # check that the packages are currently layered
@@ -95,3 +114,8 @@ vm_has_layered_packages() {
     fi
   done
 }
+
+# retrieve the checksum of the currently booted deployment
+vm_get_booted_csum() {
+  vm_get_booted_deployment_info checksum
+}

tests/vmcheck/test-layering.sh

@@ -24,15 +24,6 @@ set -e
 
 set -x
 
-# XXX: this should be done by the test harness
-test_cleanup() {
-  if vm_has_packages foo; then
-    vm_cmd rpm-ostree rollback
-    vm_reboot
-  fi
-}
-trap 'test_cleanup; _cleanup_tmpdir' EXIT
-
 # make sure package foo is not already layered
 if vm_has_files /usr/bin/foo; then
   assert_not_reached "/usr/bin/foo already present"

tests/vmcheck/test.sh

@@ -12,11 +12,23 @@ export SCP="scp -F $PWD/ssh-config"
 . ${commondir}/libvm.sh
 
 # stand up ssh connection and sanity check that it all works
-if ! vm_ssh_wait 10; then
+if ! vm_ssh_wait 20; then
   echo "ERROR: A running VM is required for 'make vmcheck'."
   exit 1
 fi
 
+unlocked_cur=$(vm_get_booted_deployment_info unlocked)
+if [[ $unlocked_cur != none ]]; then
+  echo "ERROR: VM is unlocked."
+  exit 1
+fi
+
+# remember the csum we're currently on and tag it so that ostree doesn't wipe it
+csum_orig=$(vm_get_booted_csum)
+vm_cmd ostree rev-parse $csum_orig &> /dev/null # validate
+vm_cmd ostree refs vmcheck_orig --delete
+vm_cmd ostree refs $csum_orig --create vmcheck_orig
+
 LOG=${LOG:-"$PWD/vmcheck.log"}
 echo -n '' > ${LOG}
 
@@ -51,6 +63,18 @@ for tf in $(find . -name 'test-*.sh' | sort); do
             let "failures += 1"
         fi
     fi
+
+    # go back to the original vmcheck deployment if needed
+    csum_cur=$(vm_get_booted_csum)
+    unlocked_cur=$(vm_get_booted_deployment_info unlocked)
+    if [[ $csum_orig != $csum_cur ]] || \
+       [[ $unlocked_cur != none ]]; then
+      # redeploy under the name 'vmcheck' so that tests can never modify the
+      # vmcheck_orig ref itself (e.g. package layering)
+      vm_cmd ostree commit -b vmcheck --tree=ref=vmcheck_orig
+      vm_cmd ostree admin deploy vmcheck
+      vm_reboot
+    fi
 done
 
 # tear down ssh connection