[ussuri][goal] Drop python 2.7 support and testing

OpenStack is dropping the py2.7 support in ussuri cycle.

neutron-tempest-plugin is ready with python 3 and ok to drop the
python 2.7 support.

Complete discussion & schedule can be found in
- http://lists.openstack.org/pipermail/openstack-discuss/2019-October/010142.html
- https://etherpad.openstack.org/p/drop-python2-support

Ussuri Communtiy-wide goal:
https://governance.openstack.org/tc/goals/selected/ussuri/drop-py27.html

Depends-On: https://review.opendev.org/#/c/705184/

Change-Id: I9daafef0847a9a9baa45382b87da71fe8d1fffd0

releasenotes/notes/drop-py-2-7-74b8379cab4cdc5a.yaml

@@ -0,0 +1,6 @@
+---
+upgrade:
+  - |
+    Python 2.7 support has been dropped. Last release of neutron-tempest-plugin
+    to support py2.7 is OpenStack Train. The minimum version of Python now
+    supported by neutron-tempest-plugin is Python 3.6.

requirements.txt

@@ -5,7 +5,6 @@
 pbr!=2.1.0,>=2.0.0 # Apache-2.0
 neutron-lib>=1.25.0 # Apache-2.0
 oslo.config>=5.2.0 # Apache-2.0
-ipaddress>=1.0.17;python_version<'3.3' # PSF
 netaddr>=0.7.18 # BSD
 os-ken>=0.3.0 # Apache-2.0
 oslo.log>=3.36.0 # Apache-2.0

setup.cfg

@@ -6,6 +6,7 @@ description-file =
 author = OpenStack
 author-email = openstack-discuss@lists.openstack.org
 home-page = https://opendev.org/openstack/neutron-tempest-plugin
+requires-python = >=3.6
 classifier =
     Environment :: OpenStack
     Intended Audience :: Information Technology
@@ -13,8 +14,6 @@ classifier =
     License :: OSI Approved :: Apache Software License
     Operating System :: POSIX :: Linux
     Programming Language :: Python
-    Programming Language :: Python :: 2
-    Programming Language :: Python :: 2.7
     Programming Language :: Python :: 3
     Programming Language :: Python :: 3.6
 

test-requirements.txt

@@ -7,8 +7,7 @@ hacking<0.13,>=0.12.0 # Apache-2.0
 coverage!=4.4,>=4.0 # Apache-2.0
 flake8-import-order==0.12 # LGPLv3
 python-subunit>=1.0.0 # Apache-2.0/BSD
-sphinx!=1.6.6,!=1.6.7,>=1.6.2,<2.0.0;python_version=='2.7'  # BSD
-sphinx!=1.6.6,!=1.6.7,!=2.1.0,>=1.6.2;python_version>='3.4'  # BSD
+sphinx!=1.6.6,!=1.6.7,!=2.1.0,>=1.6.2  # BSD
 oslotest>=3.2.0 # Apache-2.0
 stestr>=1.0.0 # Apache-2.0
 testtools>=2.2.0 # MIT

tox.ini

@@ -1,9 +1,11 @@
 [tox]
-minversion = 2.0
+minversion = 3.1
 envlist = pep8
 skipsdist = True
+ignore_basepython_conflict = True
 
 [testenv]
+basepython = python3
 usedevelop = True
 setenv =
    VIRTUAL_ENV={envdir}
@@ -19,7 +21,6 @@ deps =
 commands = stestr run --slowest {posargs}
 
 [testenv:pep8]
-basepython = python3
 commands =
   sh ./tools/misc-sanity-checks.sh
   flake8
@@ -27,11 +28,9 @@ whitelist_externals =
   sh
 
 [testenv:venv]
-basepython = python3
 commands = {posargs}
 
 [testenv:cover]
-basepython = python3
 setenv =
     {[testenv]setenv}
     PYTHON=coverage run --source neutron_tempest_plugin --parallel-mode
@@ -42,16 +41,13 @@ commands =
     coverage xml -o cover/coverage.xml
 
 [testenv:docs]
-basepython = python3
 commands = python setup.py build_sphinx
 
 [testenv:releasenotes]
-basepython = python3
 commands =
   sphinx-build -a -E -W -d releasenotes/build/doctrees -b html releasenotes/source releasenotes/build/html
 
 [testenv:debug]
-basepython = python3
 commands = oslo_debug_helper -t neutron_tempest_plugin/ {posargs}
 
 [flake8]