add lower-constraints job

Create a tox environment for running the unit tests against the lower
bounds of the dependencies.

Create a lower-constraints.txt to be used to enforce the lower bounds
in those tests.

Add openstack-tox-lower-constraints job to the zuul configuration.

See http://lists.openstack.org/pipermail/openstack-dev/2018-March/128352.html
for more details.

Change-Id: Ibd41a407f8f5f4eb2de1a44904fb7df5ab81e30c
Depends-On: https://review.openstack.org/555034
Signed-off-by: Doug Hellmann <doug@doughellmann.com>

.zuul.yaml

@@ -3,10 +3,12 @@
       jobs:
         - openstack-tox-functional
         - openstack-tox-functional-py35
+        - openstack-tox-lower-constraints
     gate:
       jobs:
         - openstack-tox-functional
         - openstack-tox-functional-py35
+        - openstack-tox-lower-constraints
     experimental:
       jobs:
         - barbican-simple-crypto-devstack-tempest

lower-constraints.txt

@@ -0,0 +1,145 @@
+alabaster==0.7.10
+alembic==0.8.10
+amqp==2.2.2
+appdirs==1.4.3
+asn1crypto==0.24.0
+automaton==1.14.0
+Babel==2.3.4
+bandit==1.1.0
+cachetools==2.0.1
+castellan==0.17.0
+certifi==2018.1.18
+cffi==1.11.5
+chardet==3.0.4
+cliff==2.11.0
+cmd2==0.8.1
+contextlib2==0.5.5
+coverage==4.0
+cryptography==2.1
+cursive==0.2.1
+ddt==1.0.1
+debtcollector==1.2.0
+decorator==4.2.1
+defusedxml==0.5.0
+doc8==0.6.0
+docutils==0.14
+dogpile.cache==0.6.5
+dulwich==0.19.0
+enum-compat==0.0.2
+eventlet==0.18.2
+extras==1.0.0
+fasteners==0.14.1
+fixtures==3.0.0
+flake8==2.5.5
+future==0.16.0
+futurist==1.2.0
+gitdb2==2.0.3
+GitPython==2.1.8
+glance-store==0.22.0
+greenlet==0.4.13
+hacking==0.12.0
+httplib2==0.9.1
+idna==2.6
+imagesize==1.0.0
+iso8601==0.1.11
+Jinja2==2.10
+jsonschema==2.6.0
+keystoneauth1==3.4.0
+keystonemiddleware==4.17.0
+kombu==4.1.0
+linecache2==1.0.0
+lxml==4.1.1
+Mako==1.0.7
+MarkupSafe==1.0
+mccabe==0.2.1
+mock==2.0.0
+monotonic==0.6
+mox3==0.25.0
+msgpack==0.5.6
+netaddr==0.7.19
+netifaces==0.10.6
+networkx==1.11
+openstackdocstheme==1.18.1
+os-api-ref==1.4.0
+os-client-config==1.29.0
+os-testr==1.0.0
+oslo.cache==1.29.0
+oslo.concurrency==3.26.0
+oslo.config==5.2.0
+oslo.context==2.19.2
+oslo.db==4.27.0
+oslo.i18n==3.15.3
+oslo.log==3.36.0
+oslo.messaging==5.29.0
+oslo.middleware==3.31.0
+oslo.policy==1.30.0
+oslo.serialization==2.25.0
+oslo.service==1.30.0
+oslo.utils==3.33.0
+oslotest==3.2.0
+osprofiler==1.4.0
+Paste==2.0.2
+PasteDeploy==1.5.0
+pbr==2.0.0
+pep8==1.5.7
+pika-pool==0.1.3
+pika==0.10.0
+prettytable==0.7.1
+psutil==3.2.2
+psycopg2==2.6.2
+pycadf==2.7.0
+pycparser==2.18
+pyflakes==0.8.1
+Pygments==2.2.0
+pyinotify==0.9.6
+PyMySQL==0.7.6
+pyOpenSSL==17.1.0
+pyparsing==2.2.0
+pyperclip==1.6.0
+pysendfile==2.0.0
+python-barbicanclient==4.6.0
+python-dateutil==2.7.0
+python-editor==1.0.3
+python-keystoneclient==3.8.0
+python-mimeparse==1.6.0
+python-subunit==1.2.0
+python-swiftclient==3.2.0
+pytz==2018.3
+PyYAML==3.12
+qpid-python==0.26
+reno==2.5.0
+repoze.lru==0.7
+requests==2.14.2
+requestsexceptions==1.4.0
+restructuredtext-lint==1.1.3
+retrying==1.2.3
+rfc3986==1.1.0
+Routes==2.3.1
+simplegeneric==0.8.1
+six==1.10.0
+smmap2==2.0.3
+snowballstemmer==1.2.1
+Sphinx==1.6.2
+sphinxcontrib-websupport==1.0.1
+sqlalchemy-migrate==0.11.0
+SQLAlchemy==1.0.10
+sqlparse==0.2.2
+statsd==3.2.2
+stestr==2.0.0
+stevedore==1.20.0
+taskflow==2.16.0
+Tempita==0.5.2
+tenacity==4.9.0
+testrepository==0.0.18
+testresources==2.0.0
+testscenarios==0.4
+testtools==2.2.0
+traceback2==1.4.0
+unittest2==1.1.0
+urllib3==1.22
+vine==1.1.4
+voluptuous==0.11.1
+WebOb==1.7.1
+wrapt==1.10.11
+WSME==0.8.0
+xattr==0.9.2

tox.ini

@@ -136,3 +136,10 @@ commands =
 basepython = python3.5
 commands =
   oslo_debug_helper {posargs}
+
+[testenv:lower-constraints]
+basepython = python3
+deps =
+  -c{toxinidir}/lower-constraints.txt
+  -r{toxinidir}/test-requirements.txt
+  -r{toxinidir}/requirements.txt