Improve tox.ini to easy developer's life

This patch is mainly porting from nova repository:

Adds:
1.tools/flake8wrap.sh
  Will let developer use 'tox -epep8 -- -HEAD' to testing changes files
2.tools/pretty_tox.sh
  Give pretty test trace when doing unit/functional testing.

Change-Id: Icedb4ed8b50532531e18784a1584fe63c5a9e017

test-requirements.txt

@@ -12,6 +12,7 @@ hacking<0.11,>=0.10.0 # Apache-2.0
 mock>=1.2
 oslosphinx>=2.5.0 # Apache-2.0
 oslotest>=1.10.0 # Apache-2.0
+os-testr>=0.4.1
 python-subunit>=0.0.18
 sphinx!=1.2.0,!=1.3b1,<1.3,>=1.1.2
 testrepository>=0.0.18

tools/flake8wrap.sh

@@ -0,0 +1,20 @@
+#!/bin/sh
+#
+# A simple wrapper around flake8 which makes it possible
+# to ask it to only verify files changed in the current
+# git HEAD patch.
+#
+# Intended to be invoked via tox:
+#
+#   tox -epep8 -- -HEAD
+#
+
+if test "x$1" = "x-HEAD" ; then
+    shift
+    files=$(git diff --name-only HEAD~1 | tr '\n' ' ')
+    echo "Running flake8 on ${files}"
+    diff -u --from-file /dev/null ${files} | flake8 --max-complexity 10 --diff "$@"
+else
+    echo "Running flake8 on all files"
+    exec flake8 --max-complexity 10 "$@"
+fi

tools/pretty_tox.sh

@@ -0,0 +1,16 @@
+#!/usr/bin/env bash
+
+set -o pipefail
+
+TESTRARGS=$1
+
+# --until-failure is not compatible with --subunit see:
+#
+# https://bugs.launchpad.net/testrepository/+bug/1411804
+#
+# this work around exists until that is addressed
+if [[ "$TESTARGS" =~ "until-failure" ]]; then
+    python setup.py testr --slowest --testr-args="$TESTRARGS"
+else
+    python setup.py testr --slowest --testr-args="--subunit $TESTRARGS" | subunit-trace -f
+fi

tox.ini

@@ -6,15 +6,16 @@ skipsdist = True
 [testenv]
 usedevelop = True
 install_command = pip install -U {opts} {packages}
-whitelist_externals = find
+whitelist_externals = bash
+                      find
 setenv =
    VIRTUAL_ENV={envdir}
 deps = -r{toxinidir}/requirements.txt
        -r{toxinidir}/test-requirements.txt
+passenv = http_proxy HTTP_PROXY https_proxy HTTPS_PROXY no_proxy NO_PROXY
 commands =
   find . -type f -name "*.pyc" -delete
-  python setup.py testr --slowest --testr-args='{posargs}'
-passenv = http_proxy HTTP_PROXY https_proxy HTTPS_PROXY no_proxy NO_PROXY
+  bash tools/pretty_tox.sh '{posargs}'
 
 [testenv:functional]
 sitepackages = True
@@ -22,11 +23,14 @@ setenv = OS_TEST_PATH=./magnum/tests/functional
          OS_TEST_TIMEOUT=7200
 deps =
   {[testenv]deps}
+commands =
+  find . -type f -name "*.pyc" -delete
+  bash tools/pretty_tox.sh '{posargs}'
 
 [testenv:pep8]
 commands =
   doc8 -e .rst specs/ doc/source/ contrib/ CONTRIBUTING.rst HACKING.rst README.rst
-  flake8 --max-complexity 10 {posargs}
+  bash tools/flake8wrap.sh {posargs}
 
 [testenv:venv]
 commands = {posargs}