Add test-requirements.txt

Add test-requirements.txt including files needed for docs build.

splitting this up will help with our CI infrastructure.

Change-Id: I0ee2bb1527328eac5d2b4a53b4335b42272cd56a

requirements.txt

@@ -3,5 +3,3 @@
 # process, which may cause wedges in the gate later.
 
 pbr>=2.0 # Apache-2.0
-sphinx>=1.6.2 # BSD
-openstackdocstheme>=1.11.0  # Apache-2.0

test-requirements.txt

@@ -0,0 +1,6 @@
+# The order of packages is significant, because pip processes them in the order
+# of appearance. Changing the order has an impact on the overall integration
+# process, which may cause wedges in the gate later.
+
+sphinx>=1.6.2 # BSD
+openstackdocstheme>=1.11.0  # Apache-2.0

tox.ini

@@ -7,7 +7,9 @@ skipsdist = True
 usedevelop = True
 setenv = VIRTUAL_ENV={envdir}
 install_command = pip install -U {opts} {packages}
-deps = -r{toxinidir}/requirements.txt
+deps =
+  -r{toxinidir}/requirements.txt
+  -r{toxinidir}/test-requirements.txt
 
 [testenv:venv]
 commands = {posargs}