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: Ic51680604e4a7181c4141a1b8066bb13cc9b86b7

.stestr.conf

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

test-requirements.txt

@@ -8,10 +8,10 @@ coverage!=4.4,>=4.0 # Apache-2.0
 python-subunit>=1.0.0 # Apache-2.0/BSD
 sphinx!=1.6.6,!=1.6.7,>=1.6.2 # BSD
 oslotest>=3.2.0 # Apache-2.0
-testrepository>=0.0.18 # Apache-2.0/BSD
 testtools>=2.2.0 # MIT
 openstackdocstheme>=1.18.1 # Apache-2.0
 # releasenotes
 reno>=2.5.0 # Apache-2.0
 tempest>=17.1.0 # Apache-2.0
 os-testr>=1.0.0 # Apache-2.0
+stestr>=2.0.0 # Apache-2.0

tools/pretty_tox.sh

@@ -1,7 +0,0 @@
-#! /bin/sh
-
-TESTRARGS=$1
-
-exec 3>&1
-status=$(exec 4>&1 >&3; ( python setup.py testr --slowest --testr-args="--subunit $TESTRARGS"; echo $? >&4 ) | subunit-trace -f) && exit $status
-

tox.ini

@@ -16,7 +16,7 @@ whitelist_externals = sh
                       find
 commands =
    find . -type f -name "*.pyc" -delete
-   sh tools/pretty_tox.sh '{posargs}'
+   stestr run --slowest {posargs}
 passenv = http_proxy
           HTTP_PROXY
           https_proxy