Add tox-py39 job

Change-Id: I46cac3396bd870eb1f54820921df09946184605a

doc/source/python-jobs.rst

@@ -8,6 +8,7 @@ Python Jobs
 .. zuul:autojob:: tox-py36
 .. zuul:autojob:: tox-py37
 .. zuul:autojob:: tox-py38
+.. zuul:autojob:: tox-py39
 .. zuul:autojob:: tox-docs
 .. zuul:autojob:: tox-linters
 .. zuul:autojob:: tox-molecule

zuul-tests.d/project.yaml

@@ -10,6 +10,8 @@
         - tox-py35:
             nodeset: ubuntu-xenial
         - tox-py38
+        - tox-py39:
+            nodeset: ubuntu-focal
     gate:
       jobs:
         - zuul-tox-docs
@@ -17,6 +19,8 @@
         - tox-py35:
             nodeset: ubuntu-xenial
         - tox-py38
+        - tox-py39:
+            nodeset: ubuntu-focal
     promote:
       jobs:
         - zuul-promote-docs

zuul.d/python-jobs.yaml

@@ -113,6 +113,17 @@
       tox_envlist: py38
       python_version: 3.8
 
+- job:
+    name: tox-py39
+    parent: tox
+    description: |
+      Run unit tests for a Python project under cPython version 3.9.
+
+      Uses tox with the ``py39`` environment.
+    vars:
+      tox_envlist: py39
+      python_version: 3.9
+
 - job:
     name: tox-docs
     # This is not parented to tox since we do not need