Add bindep.txt file

Bindep is a tool for checking the presence of binary packages needed
to use an application / library. It started life as a way to make it
easier to set up a development environment for OpenStack projects.

Change-Id: I1a6cfa255a6473febf0fb7b7d4f1bf8ca32d02c2
Depends-On: https://review.openstack.org/563717
Signed-off-by: Paul Belanger <pabelanger@redhat.com>

bindep.txt

@@ -0,0 +1,2 @@
+# This is a cross-platform list tracking distribution packages needed by tests;
+# see http://docs.openstack.org/infra/bindep/ for additional information.

tox.ini

@@ -93,3 +93,13 @@ deps =
   -c{toxinidir}/lower-constraints.txt
   -r{toxinidir}/test-requirements.txt
   -r{toxinidir}/requirements.txt
+
+# This environment can be used to quickly validate that all needed system
+# packages required to successfully execute test targets are installed
+[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