Use unittest.mock instead of mock

The mock third party library was needed for mock support in py2
runtimes. Since we now only support py36 and later, we can use the
standard lib unittest.mock module instead.

Note that https://github.com/openstack/charms.openstack is used during tests
and he need `mock`, unfortunatelly it doesn't declare `mock` in its
requirements so it retrieve mock from other charm project (cross dependency).
So we depend on charms.openstack first and when
Ib1ed5b598a52375e29e247db9ab4786df5b6d142 will be merged then CI
will pass without errors.

Depends-On: Ib1ed5b598a52375e29e247db9ab4786df5b6d142
Change-Id: Idcd1e9db466ec4d1ffd302dee97c453b1b822323

.zuul.yaml

@@ -1,5 +1,4 @@
 - project:
     templates:
-      - python35-charm-jobs
       - openstack-python3-ussuri-jobs
       - openstack-cover-jobs

pip.sh

@@ -0,0 +1,18 @@
+#!/usr/bin/env bash
+#
+# This file is managed centrally by release-tools and should not be modified
+# within individual charm repos.  See the 'global' dir contents for available
+# choices of tox.ini for OpenStack Charms:
+#     https://github.com/openstack-charmers/release-tools
+#
+# setuptools 58.0 dropped the support for use_2to3=true which is needed to
+# install blessings (an indirect dependency of charm-tools).
+#
+# More details on the beahvior of tox and virtualenv creation can be found at
+# https://github.com/tox-dev/tox/issues/448
+#
+# This script is wrapper to force the use of the pinned versions early in the
+# process when the virtualenv was created and upgraded before installing the
+# depedencies declared in the target.
+pip install 'pip<20.3' 'setuptools<50.0.0'
+pip "$@"

requirements.txt

@@ -3,9 +3,21 @@
 # choices of *requirements.txt files for OpenStack Charms:
 #     https://github.com/openstack-charmers/release-tools
 #
+# NOTE(lourot): This might look like a duplication of test-requirements.txt but
+# some tox targets use only test-requirements.txt whereas charm-build uses only
+# requirements.txt
 setuptools<50.0.0  # https://github.com/pypa/setuptools/commit/04e3df22df840c6bb244e9b27bc56750c44b7c85
+
 # Build requirements
-charm-tools>=2.4.4
-# importlib-resources 1.1.0 removed Python 3.5 support
-importlib-resources<1.1.0
+cffi==1.14.6; python_version < '3.6'  # cffi 1.15.0 drops support for py35.
+charm-tools==2.8.3
+
 simplejson
+
+# Newer versions use keywords that didn't exist in python 3.5 yet (e.g.
+# "ModuleNotFoundError")
+# NOTE(lourot): This might look like a duplication of test-requirements.txt but
+# some tox targets use only test-requirements.txt whereas charm-build uses only
+# requirements.txt
+importlib-metadata<3.0.0; python_version < '3.6'
+importlib-resources<3.0.0; python_version < '3.6'

test-requirements.txt

@@ -3,13 +3,47 @@
 # choices of *requirements.txt files for OpenStack Charms:
 #     https://github.com/openstack-charmers/release-tools
 #
+pyparsing<3.0.0  # aodhclient is pinned in zaza and needs pyparsing < 3.0.0, but cffi also needs it, so pin here.
+cffi==1.14.6; python_version < '3.6'  # cffi 1.15.0 drops support for py35.
 setuptools<50.0.0  # https://github.com/pypa/setuptools/commit/04e3df22df840c6bb244e9b27bc56750c44b7c85
-# Lint and unit test requirements
-flake8>=2.2.4
+
 stestr>=2.2.0
+
+# Dependency of stestr. Workaround for
+# https://github.com/mtreinish/stestr/issues/145
+cliff<3.0.0
+
+# Dependencies of stestr. Newer versions use keywords that didn't exist in
+# python 3.5 yet (e.g. "ModuleNotFoundError")
+importlib-metadata<3.0.0; python_version < '3.6'
+importlib-resources<3.0.0; python_version < '3.6'
+
+# Some Zuul nodes sometimes pull newer versions of these dependencies which
+# dropped support for python 3.5:
+osprofiler<2.7.0;python_version<'3.6'
+stevedore<1.31.0;python_version<'3.6'
+debtcollector<1.22.0;python_version<'3.6'
+oslo.utils<=3.41.0;python_version<'3.6'
+
 requests>=2.18.4
 charms.reactive
-mock>=1.2
+
 nose>=1.3.7
 coverage>=3.6
 git+https://github.com/openstack/charms.openstack.git#egg=charms.openstack
+#
+# Revisit for removal / mock improvement:
+#
+# NOTE(lourot): newer versions of cryptography require a Rust compiler to build,
+# see
+# * https://github.com/openstack-charmers/zaza/issues/421
+# * https://mail.python.org/pipermail/cryptography-dev/2021-January/001003.html
+#
+netifaces        # vault
+psycopg2-binary  # vault
+tenacity         # vault
+pbr==5.6.0       # vault
+cryptography<3.4 # vault, keystone-saml-mellon
+lxml             # keystone-saml-mellon
+hvac             # vault, barbican-vault
+psutil           # cinder-lvm

tox.ini

@@ -1,54 +1,89 @@
 # Source charm: ./tox.ini
 # This file is managed centrally by release-tools and should not be modified
-# within individual charm repos.
+# within individual charm repos.  See the 'global' dir contents for available
+# choices of tox.ini for OpenStack Charms:
+#     https://github.com/openstack-charmers/release-tools
+
 [tox]
 skipsdist = True
 envlist = pep8,py3
-# NOTE(beisner): Avoid build/test env pollution by not enabling sitepackages.
+# NOTE: Avoid build/test env pollution by not enabling sitepackages.
 sitepackages = False
-# NOTE(beisner): Avoid false positives by not skipping missing interpreters.
+# 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
+requires =
+  pip < 20.3
+  virtualenv < 20.0
+  setuptools<50.0.0
+
+# NOTE: https://wiki.canonical.com/engineering/OpenStack/InstallLatestToxOnOsci
+minversion = 3.18.0
 
 [testenv]
 setenv = VIRTUAL_ENV={envdir}
          PYTHONHASHSEED=0
          TERM=linux
          LAYER_PATH={toxinidir}/layers
+         INTERFACE_PATH={toxinidir}/interfaces
          JUJU_REPOSITORY={toxinidir}/build
-passenv = http_proxy https_proxy INTERFACE_PATH
+passenv = http_proxy https_proxy INTERFACE_PATH LAYER_PATH JUJU_REPOSITORY
 install_command =
-  pip install {opts} {packages}
+  {toxinidir}/pip.sh install {opts} {packages}
 deps =
     -r{toxinidir}/requirements.txt
 
 [testenv:build]
 basepython = python3
 commands =
-    charm-build --log-level DEBUG -o {toxinidir}/build/builds src {posargs}
+    charm-build --log-level DEBUG --use-lock-file-branches -o {toxinidir}/build/builds src {posargs}
+
+[testenv:add-build-lock-file]
+basepython = python3
+commands =
+    charm-build --log-level DEBUG --write-lock-file -o {toxinidir}/build/builds src {posargs}
 
 [testenv:py3]
 basepython = python3
 deps = -r{toxinidir}/test-requirements.txt
-commands = stestr run {posargs}
+commands = stestr run --slowest {posargs}
 
 [testenv:py35]
 basepython = python3.5
 deps = -r{toxinidir}/test-requirements.txt
-commands = stestr run {posargs}
+commands = stestr run --slowest {posargs}
 
 [testenv:py36]
 basepython = python3.6
 deps = -r{toxinidir}/test-requirements.txt
-commands = stestr run {posargs}
+commands = stestr run --slowest {posargs}
 
 [testenv:py37]
 basepython = python3.7
 deps = -r{toxinidir}/test-requirements.txt
-commands = stestr run {posargs}
+commands = stestr run --slowest {posargs}
+
+[testenv:py38]
+basepython = python3.8
+deps = -r{toxinidir}/test-requirements.txt
+commands = stestr run --slowest {posargs}
+
+[testenv:py39]
+basepython = python3.9
+deps = -r{toxinidir}/test-requirements.txt
+commands = stestr run --slowest {posargs}
 
 [testenv:pep8]
 basepython = python3
-deps = -r{toxinidir}/test-requirements.txt
+deps = flake8==3.9.2
+       charm-tools==2.8.3
 commands = flake8 {posargs} src unit_tests
 
 [testenv:cover]
@@ -62,7 +97,7 @@ setenv =
     PYTHON=coverage run
 commands =
     coverage erase
-    stestr run {posargs}
+    stestr run --slowest {posargs}
     coverage combine
     coverage html -d cover
     coverage xml -o cover/coverage.xml

unit_tests/test_watcher_handlers.py

@@ -12,7 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-import mock
+from unittest import mock
 
 import reactive.watcher_handlers as handlers