Update the URL to the upper-constraints file to point to the redirect
rule on releases.openstack.org so that anyone working on this branch
will switch to the correct upper-constraints list automatically when
the requirements repository branches.

Until the requirements repository has as stable/stein branch, tests will
continue to use the upper-constraints list on master.

Change-Id: I9b4e2056aeb5a758e7c0950ea7677d1a86c21b73

The commands used by constraints need at least tox 2.0.  Update to
reflect reality, which should help with local running of constraints
targets.

Change-Id: Ie594fc55eb54d48d96157e31a319f0ff97afc9be
Closes-Bug:  #1801691

Quotes around {posargs} cause the entire string to be combined into one
arg that gets passed to stestr. This prevents passing multiple args
(e.g. '--concurrency=16 some-regex')

Change-Id: I6ee01703bd4c432211f0d6e2f3501c989523ae11

According to Openstack summit session [1],
stestr is maintained project to which all Openstack projects should migrate.
Let's switch to stestr as other projects have already moved to it.

[1] https://etherpad.openstack.org/p/YVR-python-pti

Change-Id: I7079a92f972f5cb21e0d2077dd029701930a3590

We want to default to running all tox environments under python 3, so
set the basepython value in each environment.

We do not want to specify a minor version number, because we do not
want to have to update the file every time we upgrade python.

We do not want to set the override once in testenv, because that
breaks the more specific versions used in default environments like
py35 and py36.

Change-Id: Ia20d2ef56af2da00b374b3a3e5d79d7228c6a763
Signed-off-by: Doug Hellmann <doug@doughellmann.com>

Change testenv:debug34 to testenv:debug35

Change-Id: I49a63aabb33ff117842455d475fb8eab0e086912

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 PrettyTable dependency so the tests pass.

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

Change-Id: I59c771ca583fb0ebc9f39314ee68264410f8a173
Depends-On: https://review.openstack.org/555034
Signed-off-by: Doug Hellmann <doug@doughellmann.com>

For compliance with the Project Testing Interface as described in:
https://governance.openstack.org/tc/reference/project-testing-interface.html

Refer to:
http://lists.openstack.org/pipermail/openstack-dev/2017-November/124815.html

Change-Id: Ibb35b13fe121fa2489ef31f51e1a662fbd01cc8b
Co-Authored-By: Nguyen Hai <nguyentrihai93@gmail.com>