Use nox

This illustrates the use of nox in a simpler project. It can build docs,
run linters, and execute unittests simply and effectively.

Note we pin the packaging package as newer versions have changed
behavior on rolling release distros that don't have proper version. This
is necessary to fix gating. The followup change fixes it properly.

Change-Id: I795e4d73f60d90b0f027df43a80ebda773ee9194

.gitignore

@@ -23,6 +23,7 @@ pip-log.txt
 
 # Unit test / coverage reports
 .coverage
+.nox
 .tox
 nosetests.xml
 .testrepository

.zuul.yaml

@@ -49,7 +49,7 @@
     vars:
       release_python: python3
     templates:
-      - publish-opendev-tox-docs
+      - publish-opendev-nox-docs
     check:
       jobs:
         - bindep-centos-7
@@ -60,12 +60,15 @@
         - bindep-ubuntu-bionic
         - bindep-ubuntu-focal
         - build-python-release
-        - tox-pep8
-        - tox-py27
-        - tox-py35:
-            nodeset: ubuntu-xenial
-        - tox-py39:
-            nodeset: ubuntu-focal
+        - nox-linters
+        - nox-py27
+        - nox-py36:
+            nodeset: ubuntu-bionic
+        - nox-py310:
+            nodeset: ubuntu-jammy
+        - nox-py311:
+            nodeset: ubuntu-jammy
+        - nox-cover
     gate:
       jobs:
         - bindep-centos-7
@@ -76,12 +79,15 @@
         - bindep-ubuntu-bionic
         - bindep-ubuntu-focal
         - build-python-release
-        - tox-pep8
-        - tox-py27
-        - tox-py35:
-            nodeset: ubuntu-xenial
-        - tox-py39:
-            nodeset: ubuntu-focal
+        - nox-linters
+        - nox-py27
+        - nox-py36:
+            nodeset: ubuntu-bionic
+        - nox-py310:
+            nodeset: ubuntu-jammy
+        - nox-py311:
+            nodeset: ubuntu-jammy
+        - nox-cover
     promote:
       jobs:
         - opendev-promote-python

noxfile.py

@@ -0,0 +1,59 @@
+import nox
+
+
+nox.options.error_on_external_run = True
+nox.options.reuse_existing_virtualenvs = True
+nox.options.sessions = ["tests-3", "tests-2.7", "linters"]
+
+
+# Note setting python this way seems to give us a target name without
+# python specific suffixes while still allowing us to force a specific
+# version using --force-python.
+@nox.session(python="3")
+def linters(session):
+    session.install("hacking>=3.2.0,<3.3")
+    session.run("flake8")
+
+
+@nox.session(python="3")
+def docs(session):
+    session.install("-r", "requirements.txt")
+    session.install("-r", "doc/requirements.txt")
+    session.install(".")
+    session.run(
+        "sphinx-build", "-W",
+        "-d", "doc/build/doctrees",
+        "-b", "html",
+        "doc/source/", "doc/build/html"
+    )
+
+
+@nox.session(python="3")
+def venv(session):
+    session.install("-r", "requirements.txt")
+    session.install("-r", "test-requirements.txt")
+    session.install("-e", ".")
+    session.run(*session.posargs)
+
+
+# This will attempt to run python3 and 2.7 tests by default.
+@nox.session(python=["3", "2.7"])
+def tests(session):
+    session.install("-r", "requirements.txt")
+    session.install("-r", "test-requirements.txt")
+    session.install("-e", ".")
+    session.run("stestr", "run", *session.posargs)
+    session.run("stestr", "slowest")
+
+
+@nox.session(python="3")
+def cover(session):
+    session.install("-r", "requirements.txt")
+    session.install("-r", "test-requirements.txt")
+    session.install("-e", ".")
+    session.env["PYTHON"] = "coverage run --source bindep --parallel-mode"
+    session.run("stestr", "run", *session.posargs)
+    session.run("stestr", "slowest")
+    session.run("coverage", "combine")
+    session.run("coverage", "html", "-d", "cover")
+    session.run("coverage", "xml", "-o", "cover/coverage.xml")

requirements.txt

@@ -2,5 +2,5 @@ distro<1.7.0 ; python_version < '3.6'
 distro>=1.7.0 ; python_version >= '3.6'
 pbr>=2.0.0  # Apache-2.0
 Parsley
-packaging ; python_version >= '3.6'
+packaging<22.0 ; python_version >= '3.6'
 packaging<21.0 ; python_version < '3.6'

setup.cfg

@@ -51,3 +51,10 @@ console_scripts =
 
 [wheel]
 universal = 1
+
+[flake8]
+# E123, E125 skipped as they are invalid PEP-8.
+show-source = True
+ignore = E123,E125,E129,H,W503,W504
+builtins = _
+exclude=.venv,.git,.nox,.tox,dist,doc,*lib/python*,*egg,build

tox.ini

@@ -41,11 +41,3 @@ deps =
   -r{toxinidir}/doc/requirements.txt
 commands =
   sphinx-build -W -d doc/build/doctrees -b html doc/source/ doc/build/html
-
-[flake8]
-# E123, E125 skipped as they are invalid PEP-8.
-
-show-source = True
-ignore = E123,E125,E129,H,W503,W504
-builtins = _
-exclude=.venv,.git,.tox,dist,doc,*lib/python*,*egg,build