Use a venv with previous ansible version for upgrades

When doing the role upgrade, we run every playbook with current's
branch ansible. This is normal for the infrastructure bits (which
are running on current branch), but not for the installation of
the previous branch's role, which should use previous branch's
environment.

Change-Id: I88e2616db193487905e1e1552695ec4847bcb4f9
Depends-On: I7ebb045885dd645b820de2b7f75b46c755c015f6
Related-Bug: #1741471

tests/test-install-previous-nova.yml

@@ -15,6 +15,9 @@
 
 - include: common/previous/setting-nodepool-variables.yml
 
+# Ensure the repo is setup for previous version
+- include: common/previous/test-repo-setup.yml
+
 - name: Prepare for nova services
   hosts: nova_all
   user: root

tests/test-nova-upgrades.sh

@@ -55,7 +55,8 @@ echo "TEST_IDEMPOTENCE: ${TEST_IDEMPOTENCE}"
 function execute_ansible_playbook {
 
   export ANSIBLE_CLI_PARAMETERS="${ANSIBLE_PARAMETERS} -e @${ANSIBLE_OVERRIDES}"
-  CMD_TO_EXECUTE="ansible-playbook ${TEST_PLAYBOOK} $@ ${ANSIBLE_CLI_PARAMETERS}"
+  export ANSIBLE_BIN=${ANSIBLE_BIN:-"ansible-playbook"}
+  CMD_TO_EXECUTE="${ANSIBLE_BIN}  ${TEST_PLAYBOOK} $@ ${ANSIBLE_CLI_PARAMETERS}"
 
   echo "Executing: ${CMD_TO_EXECUTE}"
   echo "With:"
@@ -71,13 +72,29 @@ function execute_ansible_playbook {
 # Ensure that the Ansible environment is properly prepared
 source "${COMMON_TESTS_PATH}/test-ansible-env-prep.sh"
 
-# Prepare environment for the initial deploy of previous Nova
+# Prepare environment for the initial deploy of (previous and current) Nova
 # No upgrading or testing is done yet.
 export ANSIBLE_LOG_PATH="${ANSIBLE_LOG_DIR}/ansible-execute-nova-install.log"
 
+# Execute the setup of current infrastructure
+execute_ansible_playbook
+
+
+# Prepare environment for the deploy of previous Nova:
+# No upgrading or testing is done yet.
+export TEST_PLAYBOOK="${WORKING_DIR}/tests/test-install-previous-nova.yml"
+export ANSIBLE_LOG_PATH="${ANSIBLE_LOG_DIR}/ansible-execute-previous_nova-install.log"
+export PREVIOUS_VENV="ansible-previous"
+export ANSIBLE_BIN="${WORKING_DIR}/.tox/${PREVIOUS_VENV}/bin/ansible-playbook"
+source ${COMMON_TESTS_PATH}/test-create-previous-venv.sh
+
 # Execute the setup of previous Nova
 execute_ansible_playbook
 
+# Unset previous branch overrides
+unset PREVIOUS_VENV
+unset ANSIBLE_BIN
+
 # Prepare environment for the upgrade of Nova
 export TEST_PLAYBOOK="${WORKING_DIR}/tests/benchmark-upgrade.yml"
 export ANSIBLE_LOG_PATH="${ANSIBLE_LOG_DIR}/ansible-execute-nova-upgrade.log"

tests/test-upgrade.yml

@@ -27,9 +27,3 @@
 
 # Install Neutron
 - include: common/test-install-neutron.yml
-
-# Ensure the repo is setup for previous version
-- include: common/previous/test-repo-setup.yml
-
-# Install previous Nova
-- include: test-install-previous-nova.yml