Switch to stestr

According to Openstack summit session [1],
stestr is maintained project to which all Openstack projects should migrate.
Let's switch to stestr as other projects have already moved to it.

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

Change-Id: Ifeb63d8d8afa6e820afc205f22c9d31c3d80045b

.gitignore

@@ -1,4 +1,4 @@
-.testrepository
+.stestr/
 doc/build
 *.egg-info
 *.pyc

.stestr.conf

@@ -0,0 +1,4 @@
+[DEFAULT]
+test_path=./tests
+top_dir=./
+

.testr.conf

@@ -1,4 +0,0 @@
-[DEFAULT]
-test_command=${PYTHON:-python} -m subunit.run discover tests $LISTOPT $IDOPTION
-test_id_option=--load-list $IDFILE
-test_list_option=--list

requirements.txt

@@ -1,6 +1,6 @@
 oslosphinx
 pbr>=0.6,!=0.7,<1.0
 sphinx>=1.1.2,<1.2
-testrepository>=0.0.18
+stestr>=2.0.0
 testtools>=0.9.34
 yasfb>=0.5.1

tox.ini

@@ -8,7 +8,7 @@ usedevelop = True
 setenv = VIRTUAL_ENV={envdir}
 install_command = pip install -U {opts} {packages}
 deps = -r{toxinidir}/requirements.txt
-commands = python setup.py testr --slowest --testr-args='{posargs}'
+commands = stestr run --slowest {posargs}
 
 [testenv:venv]
 commands = {posargs}