Switch to use stestr for unit test

According to Openstack summit session [1],
stestr is maintained project to which all Openstack projects should migrate.
So we should switch to stestr.

[1] https://etherpad.openstack.org/p/YVR-python-pti

Change-Id: I753abb6ceae046e388357450a6cdb84af6e5fe74

.gitignore

@@ -28,7 +28,7 @@ pip-log.txt
 .tox
 nosetests.xml
 cover/*
-.testrepository/
+.stestr/
 subunit.log
 .mistral.conf
 AUTHORS

.stestr.conf

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

.testr.conf

@@ -1,7 +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 ./ . $LISTOPT $IDOPTION
-test_id_option=--load-list $IDFILE
-test_list_option=--list

requirements.txt

@@ -1,6 +1,5 @@
 oslosphinx
 pbr>=1.6
 sphinx>=1.1.2,<1.2
-testrepository>=0.0.18
 testtools>=0.9.34
 yasfb>=0.5.1

test-requirements.txt

@@ -1 +1,2 @@
 hacking>=0.12.0,!=0.13.0,<0.14  # Apache-2.0
+stestr>=2.0.0 # Apache-2.0

tox.ini

@@ -14,7 +14,7 @@ deps =
 whitelist_externals = find
 commands =
     find . -type f -name "*.pyc" -delete
-    python setup.py testr --slowest --testr-args='{posargs}'
+    stestr run --slowest {posargs}
 
 [testenv:venv]
 commands = {posargs}