Add test coverage calculation

Adds tox cover job as well.

Change-Id: Ie4f0b5e38545b61da017dbccde1442ec2c6fc382

.zuul.yaml

@@ -1,10 +1,21 @@
 ---
-
 - project:
     name: openstack/python-tempestconf
     check:
       jobs:
+        - python-tempestconf-tox-cover
         - tripleo-ci-centos-7-containers-multinode
     gate:
       jobs:
         - tripleo-ci-centos-7-containers-multinode
+
+- job:
+    name: python-tempestconf-tox-cover
+    parent: openstack-tox
+    description: Run tox code coverage tests.
+    irrelevant-files:
+      - ^.*\.rst$
+      - ^doc/.*$
+      - ^releasenotes/.*$
+    vars:
+      tox_envlist: cover

tox.ini

@@ -24,10 +24,17 @@ commands = flake8 {posargs}
 commands = {posargs}
 
 [testenv:cover]
+setenv =
+  {[testenv]setenv}
+  PYTHON=coverage run --source config_tempest --parallel-mode
 commands =
     coverage erase
     find . -type f -name "*.pyc" -delete
     stestr --test-path ./config_tempest/tests run {posargs}
+    coverage combine
+    coverage html -d cover
+    coverage xml -o cover/coverage.xml
+    coverage report
 
 [testenv:docs]
 commands = python setup.py build_sphinx