Fix charm for tox4 compatibility

Also remove python 3.5 targets as this is long not supported.

And add the mocking for charmhelpers - see
https://review.opendev.org/c/openstack/charm-heat/+/899195 for example

Related-Bug: 2002788
Change-Id: Ic70092a45d595d337ea26505139c2f6515cb1d38

build-requirements.txt

@@ -1,7 +0,0 @@
-# NOTES(lourot):
-# * We don't install charmcraft via pip anymore because it anyway spins up a
-#   container and scp the system's charmcraft snap inside it. So the charmcraft
-#   snap is necessary on the system anyway.
-# * `tox -e build` successfully validated with charmcraft 1.2.1
-
-cffi==1.14.6; python_version < '3.6'  # cffi 1.15.0 drops support for py35.

osci.yaml

@@ -15,7 +15,7 @@
       needs_charm_build: true
       charm_build_name: ceph-iscsi
       build_type: charmcraft
-      charmcraft_channel: 2.0/stable
+      charmcraft_channel: 2.2/stable
 - job:
     name: ceph-iscsi-focal-quincy
     parent: func-target

test-requirements.txt

@@ -8,9 +8,6 @@ flake8>=2.2.4,<=2.4.1
 stestr>=2.2.0
 requests>=2.18.4
 psutil
-# oslo.i18n dropped py35 support
-oslo.i18n<4.0.0
 git+https://github.com/openstack-charmers/zaza.git#egg=zaza
 git+https://github.com/openstack-charmers/zaza-openstack-tests.git#egg=zaza.openstack
-pytz    # workaround for 14.04 pip/tox
 pyudev  # for ceph-* charm unit tests (not mocked?)

tox.ini

@@ -7,44 +7,30 @@ skipsdist = True
 sitepackages = False
 # NOTE: Avoid false positives by not skipping missing interpreters.
 skip_missing_interpreters = False
-# NOTES:
-# * We avoid the new dependency resolver by pinning pip < 20.3, see
-#   https://github.com/pypa/pip/issues/9187
-# * Pinning dependencies requires tox >= 3.2.0, see
-#   https://tox.readthedocs.io/en/latest/config.html#conf-requires
-# * It is also necessary to pin virtualenv as a newer virtualenv would still
-#   lead to fetching the latest pip in the func* tox targets, see
-#   https://stackoverflow.com/a/38133283
-# * It is necessary to declare setuptools as a dependency otherwise tox will
-#   fail very early at not being able to load it. The version pinning is in
-#   line with `pip.sh`.
-requires = pip < 20.3
-           virtualenv < 20.0
-           setuptools < 50.0.0
-# NOTE: https://wiki.canonical.com/engineering/OpenStack/InstallLatestToxOnOsci
-minversion = 3.2.0
 
 [testenv]
+# We use tox mainly for virtual environment management for test requirements
+# and do not install the charm code as a Python package into that environment.
+# Ref: https://tox.wiki/en/latest/config.html#skip_install
+skip_install = True
 setenv = VIRTUAL_ENV={envdir}
          PYTHONHASHSEED=0
          CHARM_DIR={envdir}
-install_command =
-  pip install {opts} {packages}
 commands = stestr run --slowest {posargs}
 allowlist_externals =
     git
     add-to-archive.py
     bash
     charmcraft
-    rename.sh
-passenv = HOME TERM CS_* OS_* TEST_*
+    {toxinidir}/rename.sh
+passenv =
+    HOME
+    TERM
+    CS_*
+    OS_*
+    TEST_*
 deps = -r{toxinidir}/test-requirements.txt
 
-[testenv:py35]
-basepython = python3.5
-# python3.5 is irrelevant on a focal+ charm.
-commands = /bin/true
-
 [testenv:py36]
 basepython = python3.6
 deps = -r{toxinidir}/requirements.txt
@@ -70,6 +56,11 @@ basepython = python3.10
 deps = -r{toxinidir}/requirements.txt
        -r{toxinidir}/test-requirements.txt
 
+[testenv:py311]
+basepython = python3.11
+deps = -r{toxinidir}/requirements.txt
+       -r{toxinidir}/test-requirements.txt
+
 [testenv:py3]
 basepython = python3
 deps = -r{toxinidir}/requirements.txt
@@ -115,7 +106,6 @@ commands = {posargs}
 
 [testenv:build]
 basepython = python3
-deps = -r{toxinidir}/build-requirements.txt
 commands =
     charmcraft clean
     charmcraft -v pack

unit_tests/__init__.py

@@ -17,3 +17,15 @@ import mock
 
 # Mock out secrets to make py35 happy.
 sys.modules['secrets'] = mock.MagicMock()
+
+# Patch out lsb_release() and get_platform() as unit tests should be fully
+# insulated from the underlying platform.  Unit tests assume that the system is
+# ubuntu jammy.
+mock.patch(
+    'charmhelpers.osplatform.get_platform', return_value='ubuntu'
+).start()
+mock.patch(
+    'charmhelpers.core.host.lsb_release',
+    return_value={
+        'DISTRIB_CODENAME': 'jammy'
+    }).start()