Improve platform mocking

Patch out charmhelpers.osplatform.get_platform() and
charmhelpers.core.host.lsb_release() globally in the unit tests to
insulate the unit tests from the platform that the unit tests are being
run on.

Change-Id: I5336677dd9e7fbfa50cc6507b0d5ac5ef52b0070

tox.ini

@@ -18,9 +18,9 @@ skip_missing_interpreters = False
 # * 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
+requires = pip
+           virtualenv
+           setuptools
 # NOTE: https://wiki.canonical.com/engineering/OpenStack/InstallLatestToxOnOsci
 minversion = 3.2.0
 
@@ -35,8 +35,13 @@ allowlist_externals =
     git
     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]
@@ -46,46 +51,60 @@ commands = /bin/true
 
 [testenv:py36]
 basepython = python3.6
-deps = -r{toxinidir}/requirements.txt
-       -r{toxinidir}/test-requirements.txt
+deps =
+    -r{toxinidir}/requirements.txt
+    -r{toxinidir}/test-requirements.txt
 
 [testenv:py37]
 basepython = python3.7
-deps = -r{toxinidir}/requirements.txt
-       -r{toxinidir}/test-requirements.txt
+deps =
+    -r{toxinidir}/requirements.txt
+    -r{toxinidir}/test-requirements.txt
 
 [testenv:py38]
 basepython = python3.8
-deps = -r{toxinidir}/requirements.txt
-       -r{toxinidir}/test-requirements.txt
+deps =
+    -r{toxinidir}/requirements.txt
+    -r{toxinidir}/test-requirements.txt
 
 [testenv:py39]
 basepython = python3.9
-deps = -r{toxinidir}/requirements.txt
-       -r{toxinidir}/test-requirements.txt
+deps =
+    -r{toxinidir}/requirements.txt
+    -r{toxinidir}/test-requirements.txt
 
 [testenv:py310]
 basepython = python3.10
-deps = -r{toxinidir}/requirements.txt
-       -r{toxinidir}/test-requirements.txt
+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
-       -r{toxinidir}/test-requirements.txt
+deps =
+    -r{toxinidir}/requirements.txt
+    -r{toxinidir}/test-requirements.txt
 
 [testenv:pep8]
 basepython = python3
-deps = -r{toxinidir}/requirements.txt
-       -r{toxinidir}/test-requirements.txt
+deps =
+    -r{toxinidir}/requirements.txt
+    -r{toxinidir}/test-requirements.txt
 commands = flake8 {posargs} src unit_tests tests
 
 [testenv:cover]
 # Technique based heavily upon
 # https://github.com/openstack/nova/blob/master/tox.ini
 basepython = python3
-deps = -r{toxinidir}/requirements.txt
-       -r{toxinidir}/test-requirements.txt
+deps =
+    -r{toxinidir}/requirements.txt
+    -r{toxinidir}/test-requirements.txt
 setenv =
     {[testenv]setenv}
     PYTHON=coverage run
@@ -124,6 +143,7 @@ commands =
     charmcraft clean
     charmcraft -v pack
     {toxinidir}/rename.sh
+    charmcraft clean
 
 [testenv:func-noop]
 basepython = python3

unit_tests/__init__.py

@@ -11,3 +11,19 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+
+# 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.
+
+from unittest.mock import patch
+
+
+patch(
+    'charmhelpers.osplatform.get_platform', return_value='ubuntu'
+).start()
+patch(
+    'charmhelpers.core.host.lsb_release',
+    return_value={
+        'DISTRIB_CODENAME': 'jammy'
+    }).start()