Use stestr for unit tests

Change-Id: Iea1a284d06a5159d45e1e65b4c104c7a228f7c23

tox.ini

@@ -10,7 +10,7 @@ deps =
        -c{env:UPPER_CONSTRAINTS_FILE:https://git.openstack.org/cgit/openstack/requirements/plain/upper-constraints.txt}
        -r{toxinidir}/requirements.txt
        -r{toxinidir}/test-requirements.txt
-commands = python setup.py test --slowest --testr-args='{posargs}'
+commands = stestr run {posargs}
 whitelist_externals = bash
 
 [testenv:pep8]
@@ -24,7 +24,15 @@ commands = {posargs}
 
 [testenv:cover]
 basepython = python3
-commands = python setup.py test --coverage --coverage-package-name=tripleo_common --testr-args='{posargs}'
+setenv =
+  PYTHON=coverage run --source tripleo_common --parallel-mode
+commands =
+  coverage erase
+  stestr run {posargs}
+  coverage combine
+  coverage html -d cover
+  coverage xml -o cover/coverage.xml
+  coverage report
 
 [testenv:docs]
 basepython = python3