add constraints file to tox.ini

We need this to test the branching script.

Change-Id: Ie4df9b04045a9bd5d1f2996f225344ded56aed16
Signed-off-by: Doug Hellmann <doug@doughellmann.com>

tox.ini

@@ -1,15 +1,17 @@
 [tox]
 minversion = 2.0
-envlist = py34,py27,pypy,pep8
-skipsdist = True
+distribute = False
+envlist = py35,py27,pep8
 
 [testenv]
-usedevelop = True
-install_command =  pip install -U {opts} {packages}
-setenv =
-   VIRTUAL_ENV={envdir}
-deps = -r{toxinidir}/test-requirements.txt
-commands = python setup.py test --slowest --testr-args='{posargs}'
+install_command = pip install {opts} {packages}
+deps =
+  -c{env:UPPER_CONSTRAINTS_FILE:https://git.openstack.org/cgit/openstack/requirements/plain/upper-constraints.txt}
+  -r{toxinidir}/test-requirements.txt
+  -r{toxinidir}/requirements.txt
+commands =
+  python setup.py test --coverage --coverage-package-name=oslo_config --slowest --testr-args='{posargs}'
+  coverage report --show-missing
 
 [testenv:pep8]
 commands = flake8 {posargs}