Switch from testr to stestr for unit tests

Change-Id: I4bcbcae51e3f207396f10d5651e09dd1d94161fb

.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

test-requirements.txt

@@ -1,5 +1,5 @@
 # Lint and unit test requirements
 flake8
-os-testr>=0.4.1
+stestr>=2.2.0
 charms.reactive
 coverage>=3.6

tox.ini

@@ -16,12 +16,12 @@ install_command =
 [testenv:py3]
 basepython = python3
 deps = -r{toxinidir}/test-requirements.txt
-commands = ostestr {posargs}
+commands = stestr run {posargs}
 
 [testenv:py35]
 basepython = python3.5
 deps = -r{toxinidir}/test-requirements.txt
-commands = ostestr {posargs}
+commands = stestr run {posargs}
 
 [testenv:pep8]
 basepython = python3