Automatically select python version on scenario and fucntional tests

Change-Id: I6da8e7fd15f913758c562bcc5aa7baca6a9692a2

roles/run-tox/defaults/main.yaml

@@ -1,3 +1,3 @@
 tox_dir: /opt/stack/tobiko
-tox_envlist: neutron
+tox_envlist: scenario
 tox_extra_args: ''

roles/run-tox/tasks/main.yaml

@@ -1,5 +1,5 @@
 - name: Run Tobiko
-  command: tox -e {{tox_envlist}} {{tox_extra_args}}
+  command: tools/ci/tox -e {{tox_envlist}} {{tox_extra_args}}
   args:
     chdir: "{{tox_dir}}"
   become: true

tools/ci/tox

@@ -0,0 +1,23 @@
+#!/bin/bash
+
+set -eux
+
+# Prefer python3 on python2
+PYTHON=$(which python3 || which python)
+
+# Create a virtualenv for executing Tox and activate it
+BASE_VIRTUALENV_DIR=.tox/base
+if ! [ -d "${BASE_VIRTUALENV_DIR}" ]; then
+    "${PYTHON}" -m virtualenv "${BASE_VIRTUALENV_DIR}"
+    set +eux
+    source "${BASE_VIRTUALENV_DIR}/bin/activate"
+    set -eux
+    curl https://bootstrap.pypa.io/get-pip.py | python
+    pip install --upgrade setuptools wheel virtualenv tox
+else
+    set +eux
+    source "${BASE_VIRTUALENV_DIR}/bin/activate"
+    set -eux
+fi
+
+tox "$*"

tox.ini

@@ -38,7 +38,6 @@ commands = {[base]commands}
 
 [testenv:cover]
 
-basepython = python3
 setenv =
     {[testenv]setenv}
     PYTHON=coverage run --parallel-mode
@@ -106,7 +105,6 @@ commands = {[base]commands}
 
 [testenv:functional]
 
-basepython = python3
 deps = {[openstack]deps}
 passenv = {[openstack]passenv}
 setenv = {[openstack]setenv}