Add ProjectTestingInterface to horizon.

Horizon is the last project that doesn't have support for the common
Project Testing Interface. This gets horizon up to speed with the
other bits, but shouldn't break any of the existing interfaces.

Change-Id: I464c3b10d9708a0b7b5ffd42c88cd3cf515ef6a7

tox.ini

@@ -0,0 +1,46 @@
+[tox]
+envlist = py26,py27,pep8
+
+[testenv]
+setenv = VIRTUAL_ENV={envdir}
+         NOSE_WITH_OPENSTACK=1
+         NOSE_OPENSTACK_COLOR=1
+         NOSE_OPENSTACK_RED=0.05
+         NOSE_OPENSTACK_YELLOW=0.025
+         NOSE_OPENSTACK_SHOW_ELAPSED=1
+deps = -r{toxinidir}/tools/pip-requires
+       -r{toxinidir}/tools/test-requires
+commands = /bin/bash run_tests.sh -N
+
+[testenv:pep8]
+deps = pep8
+commands = /bin/bash run_tests.sh -N --pep8
+
+[testenv:venv]
+commands = {posargs}
+
+[testenv:cover]
+commands = /bin/bash run_tests.sh -N --coverage
+
+[tox:jenkins]
+downloadcache = ~/cache/pip
+
+[testenv:jenkins26]
+setenv = NOSE_WITH_XUNIT=1
+basepython = python2.6
+
+[testenv:jenkins27]
+setenv = NOSE_WITH_XUNIT=1
+basepython = python2.7
+
+[testenv:jenkinspep8]
+setenv = NOSE_WITH_XUNIT=1
+commands = /bin/bash run_tests.sh -N --pep8
+
+[testenv:jenkinscover]
+setenv = NOSE_WITH_XUNIT=1
+commands = /bin/bash run_tests.sh -N --coverage
+
+[testenv:jenkinsvenv]
+setenv = NOSE_WITH_XUNIT=1
+commands = {posargs}