Add functional-py39 testing

This patch adds both a tox target and a zuul job to run functional tests
with python3.9

Depends-On: https://review.opendev.org/760932

Change-Id: I672904e9bfb45a66a82331063c7d49c4bc0439df

.zuul.yaml

@@ -56,6 +56,28 @@
       bindep_profile: test py38
     timeout: 3600
 
+- job:
+    name: nova-tox-functional-py39
+    parent: openstack-tox-functional-py39
+    description: |
+      Run tox-based functional tests for the OpenStack Nova project
+      under cPython version 3.9 with Nova specific irrelevant-files list.
+      Uses tox with the ``functional-py39`` environment.
+
+      This job also provides a parent for other projects to run the nova
+      functional tests on their own changes.
+    required-projects:
+      # including nova here makes this job reusable by other projects
+      - openstack/nova
+      - openstack/placement
+    irrelevant-files: *functional-irrelevant-files
+    vars:
+      # explicitly stating the work dir makes this job reusable by other
+      # projects
+      zuul_work_dir: src/opendev.org/openstack/nova
+      bindep_profile: test py39
+    timeout: 3600
+
 - job:
     name: nova-live-migration
     parent: tempest-multinode-full-py3
@@ -424,6 +446,8 @@
         - nova-multi-cell
         - nova-next
         - nova-tox-functional-py38
+        - nova-tox-functional-py39:
+            voting: false
         - tempest-integrated-compute:
             # NOTE(gmann): Policies changes do not need to run all the
             # integration test jobs. Running only tempest and grenade

tox.ini

@@ -118,6 +118,13 @@ deps = {[testenv:functional]deps}
 commands =
   {[testenv:functional]commands}
 
+[testenv:functional-py39]
+description =
+  Run functional tests using python3.9.
+deps = {[testenv:functional]deps}
+commands =
+  {[testenv:functional]commands}
+
 [testenv:api-samples]
 setenv =
   {[testenv]setenv}