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.

Update the dependencies needed to make the unit tests pass while
constrained to the lower bounds.

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

Co-Authored-By: Nguyen Hai <nguyentrihai93@gmail.com>
Change-Id: I2a8f465c8b08370517cbec857933b08fca94ca38
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 015913c..660248b 100644
--- a/tox.ini
+++ b/tox.ini
@@ -70,3 +70,10 @@ commands = bindep test
 
 [testenv:releasenotes]
 commands = sphinx-build -a -W -E -d releasenotes/build/doctrees -b html releasenotes/source releasenotes/build/html
+
+[testenv:lower-constraints]
+basepython = python3
+deps =
+  -c{toxinidir}/lower-constraints.txt
+  -r{toxinidir}/test-requirements.txt
+  .[keystone]