Follow-up patch for fixing coverage issue

Signed-off-by: HeroicHitesh <email.hiteshkumar@gmail.com>
Change-Id: Ief1c7eb6b3f3d28e9321280718df59eebaca786f

.zuul.yaml

@@ -5,3 +5,4 @@
       - openstackclient-plugin-jobs
       - publish-openstack-docs-pti
       - release-notes-jobs-python3
+      - openstack-cover-jobs

tox.ini

@@ -13,7 +13,7 @@ deps =
        -c{env:TOX_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/master}
        -r{toxinidir}/requirements.txt
        -r{toxinidir}/test-requirements.txt
-commands = stestr run --slowest '{posargs}'
+commands = stestr run --slowest {posargs}
 
 [testenv:pep8]
 commands = flake8
@@ -22,7 +22,19 @@ commands = flake8
 commands = {posargs}
 
 [testenv:cover]
-commands = stestr run --coverage '{posargs}'
+basepython = python3
+allowlist_externals = find
+setenv =
+  {[testenv]setenv}
+  PYTHON=coverage run --source vitrageclient --parallel-mode
+commands =
+  coverage erase
+  find . -type f -name "*.pyc" -delete
+  stestr run {posargs}
+  coverage combine
+  coverage html -d cover
+  coverage xml -o cover/coverage.xml
+  coverage report
 
 [testenv:docs]
 deps =