Add fast8 check for cybrog

Add "tox -e fast8" command, that we can check the changes file whether
is ok of it's PEP8 format.

Change-Id: I370bc8449321932831df4fe783be5c9ff0ed65df

tools/flake8wrap.sh

@@ -0,0 +1,27 @@
+#!/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}"
+    echo ""
+    echo "Consider using the 'pre-commit' tool instead."
+    echo ""
+    echo "    pip install --user pre-commit"
+    echo "    pre-commit install --allow-missing-config"
+    echo ""
+    diff -u --from-file /dev/null ${files} | flake8 --diff "$@"
+else
+    echo "Running flake8 on all files"
+    echo ""
+    exec flake8 "$@"
+fi

tox.ini

@@ -11,6 +11,7 @@ ignore_basepython_conflict = True
 basepython = python3
 usedevelop = True
 whitelist_externals =
+  bash
   rm
   make
 install_command = {[testenv:common-constraints]install_command}
@@ -50,7 +51,6 @@ deps = bindep
 commands = bindep test
 usedevelop = False
 
-
 [testenv:pep8]
 commands =
     flake8
@@ -60,6 +60,13 @@ commands =
 install_command = {[testenv:common-constraints]install_command}
 commands = flake8 {posargs}
 
+[testenv:fast8]
+description =
+  Run style checks on the changes made since HEAD~. For a full run including docs, use 'pep8'
+envdir = {toxworkdir}/shared
+commands =
+  bash tools/flake8wrap.sh -HEAD
+
 [testenv:venv]
 commands = {posargs}