Migrate from testr to stestr

* Replace .testr.conf by .stestr.conf for migration and update
  .gitignore, tox.ini and test-requirements.txt files accordingly
* Use py3 as the default runtime for tox

Signed-off-by: HeroicHitesh <email.hiteshkumar@gmail.com>
Change-Id: Ibeb39fd9293ad037b038857507eeb498856036e3

.gitignore

@@ -1,13 +1,22 @@
-*~
-.testrepository
-*.sw?
 *.pyc
+
+# Unit test / coverage reports
+.stestr
 .tox
+.venv
+
+# Packages
 *.egg-info
 dist
 build
+
+# pbr generates these
 AUTHORS
 ChangeLog
 
+# Editors
+*.sw?
+*~
+
 # Files created by releasenotes build
 releasenotes/build

.stestr.conf

@@ -0,0 +1,3 @@
+[DEFAULT]
+test_path=./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:-160} \
-             ${PYTHON:-python} -m subunit.run discover -t ./ ./tests $LISTOPT $IDOPTION
-
-test_id_option=--load-list $IDFILE
-test_list_option=--list

test-requirements.txt

@@ -5,4 +5,4 @@
 hacking>=3.0.1,<3.1.0 # Apache-2.0
 oslotest
 
-testrepository>=0.0.18
+stestr>=2.0.0 # Apache-2.0

tox.ini

@@ -11,8 +11,7 @@ deps =
        -c{env:TOX_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/master}
        -r{toxinidir}/requirements.txt
        -r{toxinidir}/test-requirements.txt
-commands=
-    python setup.py testr --slowest --testr-args='{posargs}'
+commands = stestr run --slowest {posargs}
 
 [testenv:venv]
 commands = {posargs}