Migrate from testr to stestr

Also add .zuul.yaml to allow charm to run test and merge.

Change-Id: Icac06e1de342ae52a65345e4268ecd39a7cf15f3

.gitreview

@@ -0,0 +1,4 @@
+[gerrit]
+host=review.opendev.org
+port=29418
+project=openstack/charm-interface-nova-cell.git

.stestr.conf

@@ -0,0 +1,3 @@
+[DEFAULT]
+test_path=./unit_tests
+top_dir=./

.testr.conf

@@ -1,8 +0,0 @@
-[DEFAULT]
-test_command=OS_STDOUT_CAPTURE=${OS_STDOUT_CAPTURE:-1} \
-             OS_STDERR_CAPTURE=${OS_STDERR_CAPTURE:-1} \
-             OS_TEST_TIMEOUT=${OS_TEST_TIMEOUT:-60} \
-             ${PYTHON:-python} -m subunit.run discover -t ./ ./unit_tests $LISTOPT $IDOPTION
-
-test_id_option=--load-list $IDFILE
-test_list_option=--list

.zuul.yaml

@@ -0,0 +1,3 @@
+- project:
+    templates:
+      - openstack-python3-charm-jobs

test-requirements.txt

@@ -1,6 +1,6 @@
 # Lint and unit test requirements
 flake8
-os-testr>=0.4.1
+stestr>=2.2.0
 charms.reactive
 mock>=1.2
 coverage>=3.6

tox.ini

@@ -1,6 +1,6 @@
 [tox]
 skipsdist = True
-envlist = pep8,py35
+envlist = pep8,py36
 skip_missing_interpreters = True
 
 [testenv]
@@ -11,17 +11,22 @@ install_command =
   pip install {opts} {packages}
 
 [testenv:py35]
-basepython = python3
+basepython = python3.5
 deps = -r{toxinidir}/test-requirements.txt
-commands = ostestr {posargs}
+commands = stestr run {posargs}
 
 [testenv:py36]
 basepython = python3.6
 deps = -r{toxinidir}/test-requirements.txt
-commands = ostestr {posargs}
+commands = stestr run {posargs}
+
+[testenv:py3]
+basepython = python3
+deps = -r{toxinidir}/test-requirements.txt
+commands = stestr run {posargs}
 
 [testenv:pep8]
-basepython = python2.7
+basepython = python3
 deps = -r{toxinidir}/test-requirements.txt
 commands = flake8 {posargs} . unit_tests