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: I06a45ffdb95e4c79edeca179254f25252d9fef6e

.gitignore

@@ -25,8 +25,6 @@ pip-log.txt
 # Unit test / coverage reports
 .coverage
 .tox
-nosetests.xml
-.testrepository
 .stestr
 .venv
 

lower-constraints.txt

@@ -143,7 +143,6 @@ stestr==2.0.0
 stevedore==1.28.0
 Tempita==0.5.2
 tenacity==4.9.0
-testrepository==0.0.20
 testresources==2.0.0
 testscenarios==0.4
 testtools==2.2.0

test-requirements.txt

@@ -17,6 +17,7 @@ testresources>=2.0.0 # Apache-2.0/BSD
 testscenarios>=0.4 # Apache-2.0/BSD
 testtools>=2.2.0 # MIT
 redis>=2.10.0 # MIT
+stestr>=2.0.0 # Apache-2.0
 hiredis>=0.2.0 # BSD
 reno>=2.5.0 # Apache-2.0
 PrettyTable<0.8,>=0.7.2 # BSD

tox.ini

@@ -15,7 +15,7 @@ deps = -c{env:UPPER_CONSTRAINTS_FILE:https://git.openstack.org/cgit/openstack/re
        -r{toxinidir}/test-requirements.txt
 whitelist_externals = sh /bin/rm
 commands = /bin/rm -f .testrepository/times.dbm
-  ostestr '{posargs}'
+  stestr run {posargs}
 
 [testenv:fullstack]
 basepython = python2.7
@@ -36,9 +36,14 @@ commands = {toxinidir}/tools/generate_config_file_samples.sh
 commands = {posargs}
 
 [testenv:cover]
+setenv =
+    PYTHON=coverage run --source $project --parallel-mode
 commands =
-  python setup.py testr --coverage --testr-args='{posargs}'
-  coverage report
+    stestr run '{posargs}'
+    coverage combine
+    coverage html -d cover
+    coverage xml -o cover/coverage.xml
+    coverage report
 
 [testenv:releasenotes]
 commands = sphinx-build -a -E -W -d releasenotes/build/doctrees -b html releasenotes/source releasenotes/build/html