Switch to using stestr

According to Openstack summit session [1] stestr is maintained
project to which all Openstack projects should migrate.
Let's switch it then.

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

Change-Id: I6f7d8766969bce4efd5c0bc36df2d583800e1e3e

.stestr.conf

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

tox.ini

@@ -15,25 +15,24 @@ whitelist_externals = bash
                       find
                       rm
                       env
-# By default ostestr will set concurrency
+# By default stestr will set concurrency
 # to ncpu, to specify something else use
 # the concurrency=<n> option.
 # call ie: 'tox -epy27 -- --concurrency=4'
 commands =
   find . -type f -name "*.pyc" -delete
-  rm -Rf .testrepository/times.dbm
 passenv = http_proxy HTTP_PROXY https_proxy HTTPS_PROXY no_proxy NO_PROXY OS_DEBUG GENERATE_HASHES
 
 [testenv:py27]
 commands =
     {[testenv]commands}
-    ostestr '{posargs}'
+    stestr run {posargs}
 
 [testenv:py36]
 basepython = python3.6
 commands =
     {[testenv]commands}
-    ostestr '{posargs}'
+    stestr run {posargs}
 
 [testenv:genconfig]
 basepython = python3
@@ -49,7 +48,14 @@ commands = {posargs}
 
 [testenv:cover]
 basepython = python3
-commands = python setup.py test --coverage --testr-args='{posargs}'
+setenv =
+    VIRTUAL_ENV={envdir}
+    PYTHON=coverage run --source masakarimonitors --parallel-mode
+commands =
+    stestr run {posargs}
+    coverage combine
+    coverage html -d cover
+    coverage xml -o cover/coverage.xml
 
 [testenv:docs]
 basepython = python3