Include support for using oslo debugger in tests

Simply run `tox -e debug <test_name>` to get an interactive
debugging prompt

Change-Id: I09e5b844a33c2f0fd4230f01fbc6c0aa8d752545

test-requirements.txt

@@ -8,6 +8,7 @@ discover
 fixtures>=0.3.14
 mock>=1.0
 oslosphinx>=2.2.0  # Apache-2.0
+oslotest>=1.2.0  # Apache-2.0
 requests-mock>=0.4.0  # Apache-2.0
 sphinx>=1.1.2,!=1.2.0,!=1.3b1,<1.3
 testrepository>=0.0.18

tox.ini

@@ -25,6 +25,9 @@ commands = {posargs}
 [testenv:cover]
 commands = python setup.py test --coverage --testr-args='{posargs}'
 
+[testenv:debug]
+commands = oslo_debug_helper -t openstackclient/tests {posargs}
+
 [tox:jenkins]
 downloadcache = ~/cache/pip