Fix test coverage tox command for patrole.

Currently, tox -ecover doesn't work. This patch simply uses
nosetests and nosecover to generate a correct coverage report for
unit tests.

Change-Id: Ib7093796ead2bbef5c588c304336582f06ddd1c3

test-requirements.txt

@@ -2,12 +2,14 @@
 # of appearance. Changing the order has an impact on the overall integration
 # process, which may cause wedges in the gate later.
 hacking>=0.12.0,!=0.13.0,<0.14  # Apache-2.0
-# needed for doc build
+
 sphinx>=1.2.1,!=1.3b1,<1.4  # BSD
 oslosphinx>=4.7.0 # Apache-2.0
 reno>=1.8.0 # Apache-2.0
 mock>=2.0 # BSD
 coverage>=4.0 # Apache-2.0
+nose # LGPL
+nosexcover # BSD
 oslotest>=1.10.0 # Apache-2.0
 oslo.policy>=1.17.0  # Apache-2.0
 oslo.log>=3.11.0 # Apache-2.0

tox.ini

@@ -28,7 +28,15 @@ commands = check-uuid --fix
 commands = {posargs}
 
 [testenv:cover]
-commands = python setup.py test --coverage --testr-args='{posargs}'
+setenv = VIRTUAL_ENV={envdir}
+         NOSE_WITH_COVERAGE=1
+         NOSE_COVER_BRANCHES=1
+         NOSE_COVER_PACKAGE=patrole_tempest_plugin
+         NOSE_COVER_HTML=1
+         NOSE_COVER_HTML_DIR={toxinidir}/cover
+         NOSE_WHERE=patrole_tempest_plugin/tests/unit
+whitelist_externals = nosetests
+commands = nosetests {posargs}
 
 [testenv:docs]
 commands = python setup.py build_sphinx