vici: Add tox.ini to run tests with tox

Some of the interpreters might not be available on the host system, use
--skip-missing-interpreters to not fail in that case.

src/libcharon/plugins/vici/python/.gitignore

@@ -1,3 +1,4 @@
+.tox
 *.pyc
 build
 dist

src/libcharon/plugins/vici/python/Makefile.am

@@ -1,5 +1,6 @@
 EXTRA_DIST = LICENSE README.rst MANIFEST.in \
 	setup.py.in \
+	tox.ini \
 	vici/test/__init__.py \
 	vici/test/test_protocol.py \
 	vici/__init__.py \

src/libcharon/plugins/vici/python/tox.ini

@@ -0,0 +1,16 @@
+[tox]
+envlist = py27, py35, py36, py37, py38
+
+[testenv]
+deps =
+	pytest
+	pytest-pycodestyle
+commands = pytest --pycodestyle
+
+[testenv:py27]
+deps = pytest
+commands = pytest
+
+[pycodestyle]
+max-line-length = 80
+show-source = True