Add tox -e functional

Provide a tox -e functional stub, as a place for functional tests to
migrate to. This will allow us to write a zuul test configuration for this
environment.

Part of bp:functional-tests-for-nova

Change-Id: I8a1107beab151f9bf574cfbae1d4dc18400fd74e

Author: sdague

.testr.conf

@@ -2,7 +2,7 @@
 test_command=OS_STDOUT_CAPTURE=${OS_STDOUT_CAPTURE:-1} \
              OS_STDERR_CAPTURE=${OS_STDERR_CAPTURE:-1} \
              OS_TEST_TIMEOUT=${OS_TEST_TIMEOUT:-160} \
-             ${PYTHON:-python} -m subunit.run discover -t ./ ./nova/tests $LISTOPT $IDOPTION
+             ${PYTHON:-python} -m subunit.run discover -t ./ ${OS_TEST_PATH:-./nova/tests} $LISTOPT $IDOPTION
 
 test_id_option=--load-list $IDFILE
 test_list_option=--list

nova/tests/functional/__init__.py

@@ -28,6 +28,17 @@ downloadcache = ~/cache/pip
 commands =
   flake8 {posargs}
 
+[testenv:functional]
+usedevelop = True
+install_command = pip install -U --force-reinstall {opts} {packages}
+setenv = VIRTUAL_ENV={envdir}
+       OS_TEST_PATH=./nova/tests/functional
+deps = -r{toxinidir}/requirements.txt
+       -r{toxinidir}/test-requirements.txt
+commands =
+  find . -type f -name "*.pyc" -delete
+  bash tools/pretty_tox.sh '{posargs}'
+
 [testenv:genconfig]
 commands =
   bash tools/config/generate_sample.sh -b . -p nova -o etc/nova