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: I8d773d4ee3d0835fb2a9183fe2154e82db085bd5
Depends-On: https://review.openstack.org/555034
Signed-off-by: Doug Hellmann <doug@doughellmann.com>

1 files changed, 7 insertions, 0 deletions

diff --git a/tox.ini b/tox.ini
index 935d3e8c..53834d6f 100644
--- a/tox.ini
+++ b/tox.ini
@@ -95,3 +95,10 @@ envdir = {toxworkdir}/venv
 commands =
   oslo-config-generator --config-file=tools/config/ipa-config-generator.conf
 
+
+[testenv:lower-constraints]
+basepython = python3
+deps =
+  -c{toxinidir}/lower-constraints.txt
+  -r{toxinidir}/test-requirements.txt
+  -r{toxinidir}/requirements.txt