Allow tox to support regexes for unit tests

This patch set adds a shell wrapper script to allow
tox to be used to run a subset of unit tests via regexes:

To run all unit tests, execute::

  $ tox -epy35

To run unit tests using a regex, execute::

  $ tox -epy35 -- <regex>

Change-Id: I2ba1e18226d686cb549a075e020ba02e24204829

doc/source/developer-overview.rst

@@ -124,6 +124,17 @@ All Pegleg tests are nested under ``tests``.
 Pegleg comes equipped with a number of `tox`_ targets for running unit tests,
 as well as `pep8`_ and `Bandit`_ checks.
 
+Unit Tests
+----------
+
+To run all unit tests, execute::
+
+  $ tox -epy35
+
+To run unit tests using a regex, execute::
+
+  $ tox -epy35 -- <regex>
+
 .. _Airship: https://airshipit.readthedocs.io
 .. _Deckhand: https://airship-deckhand.readthedocs.io/
 .. _Airship coding conventions: https://airshipit.readthedocs.io/en/latest/conventions.html

tools/gate/run-unit-tests.sh

@@ -0,0 +1,10 @@
+#!/usr/bin/env bash
+
+set -e
+posargs=$@
+if [ ${#posargs} -ge 1 ]; then
+    pytest -k  ${posargs}
+else
+    pytest
+fi
+set +e

tox.ini

@@ -18,8 +18,7 @@ whitelist_externals =
   find
 commands =
   find . -type f -name "*.pyc" -delete
-  pytest \
-    {posargs}
+  {toxinidir}/tools/gate/run-unit-tests.sh '{posargs}'
 
 [testenv:fmt]
 basepython=python3