List system dependencies for running common tests

Add a bindep.txt file containing a cross-platform list
of dependencies needed for running included tox-based tests. Also
include a tox environment for convenience calling the bindep[*]
utility to list any missing system requirements.

This change is self-testing.

For bindep.txt see also
http://docs.openstack.org/infra/manual/drivers.html#package-requirements

[*] http://docs.openstack.org/infra/bindep/

Change-Id: I4046952603dddcd7290ec13be26fd09ea7fc608a

bindep.txt

@@ -0,0 +1,15 @@
+# This is a cross-platform list tracking distribution packages needed by tests;
+# see http://docs.openstack.org/infra/bindep/ for additional information.
+
+build-essential [platform:dpkg]
+gcc [platform:rpm]
+gettext
+liberasurecode-dev [platform:dpkg]
+liberasurecode-devel [platform:rpm]
+libffi-dev [platform:dpkg]
+libffi-devel [platform:rpm]
+memcached
+python-dev [platform:dpkg]
+python-devel [platform:rpm]
+rsync
+xfsprogs

tox.ini

@@ -61,3 +61,11 @@ commands = {posargs}
 ignore = F812,H101,H202,H233,H234,H301,H306,H401,H403,H404,H405,H501,H703
 exclude = .venv,.tox,dist,doc,*egg,test
 show-source = True
+
+[testenv:bindep]
+# Do not install any requirements. We want this to be fast and work even if
+# system dependencies are missing, since it's used to tell you what system
+# dependencies are missing! This also means that bindep must be installed
+# separately, outside of the requirements files.
+deps = bindep
+commands = bindep test