# tox-2.0: plugins, platform, env isolation

tox-2.0 was released to pypi, a major new release with mostly backward-compatible enhancements and fixes:

- experimental support for plugins, see https://testrun.org/tox/latest/plugins.html which includes also a refined internal registration mechanism for new testenv ini options. You can now ask tox which testenv ini parameters exist with `tox --help-ini`.
- ENV isolation: only pass through very few environment variables from the tox invocation to the test environments. This may break test runs that previously worked with tox-1.9 – you need to either use the `setenv` or `passenv` ini variables to set appropriate environment variables.
- PLATFORM support: you can set `platform=REGEX` in your testenv sections which lets tox skip the environment if the REGEX does not match `sys.platform`.
- tox now stops execution of test commands if the first of them fails unless you set `ignore_errors=True`.

Thanks to Volodymyr Vitvitski, Daniel Hahler, Marc Abramowitz, Anthon van der Neuth and others for contributions.

More documentation about tox in general:

> http://tox.testrun.org/

Installation:

> pip install -U tox

code hosting and issue tracking on bitbucket:

> https://bitbucket.org/hpk42/tox

## What is tox?

tox standardizes and automates tedious test activities driven from a simple `tox.ini` file, including:

- creation and management of different virtualenv environments with different Python interpreters
- packaging and installing your package into each of them
- running your test tool of choice, be it nose, py.test or unittest2 or other tools such as “sphinx” doc checks
- testing dev packages against each other without needing to upload to PyPI

best, Holger Krekel, merlinux GmbH

## 2.0.0

- (new) introduce environment variable isolation: tox now only passes the PATH and PIP_INDEX_URL variable from the tox invocation environment to the test environment and on Windows also `SYSTEMROOT`, `PATHEXT`, `TEMP` and `TMP` whereas on unix additionally `TMPDIR` is passed. If you need to pass through further environment variables you can use the new `passenv` setting, a space-separated list of environment variable names. Each name can make use of fnmatch-style glob patterns. All environment variables which exist in the tox-invocation environment will be copied to the test environment.

- a new `--help-ini` option shows all possible testenv settings and their defaults.

- (new) introduce a way to specify on which platform a testenvironment is to execute: the new per-venv “platform” setting allows to specify a regular expression which is matched against sys.platform. If platform is set and doesn’t match the platform spec in the test environment the test environment is ignored, no setup or tests are attempted.

- (new) add per-venv “ignore_errors” setting, which defaults to False.

    If `True`, a non-zero exit code from one command will be ignored and further commands will be executed (which was the default behavior in tox < 2.0). If `False` (the default), then a non-zero exit code from one command will abort execution of commands for that environment.

- show and store in json the version dependency information for each venv

- remove the long-deprecated “distribute” option as it has no effect these days.

- fix issue233: avoid hanging with tox-setuptools integration example. Thanks simonb.

- fix issue120: allow substitution for the commands section. Thanks Volodymyr Vitvitski.

- fix issue235: fix AttributeError with –installpkg. Thanks Volodymyr Vitvitski.

- tox has now somewhat pep8 clean code, thanks to Volodymyr Vitvitski.

- fix issue240: allow to specify empty argument list without it being rewritten to ”.”. Thanks Daniel Hahler.

- introduce experimental (not much documented yet) plugin system based on pytest’s externalized “pluggy” system. See tox/hookspecs.py for the current hooks.

- introduce parser.add_testenv_attribute() to register an ini-variable for testenv sections. Can be used from plugins through the tox_add_option hook.

- rename internal files – tox offers no external API except for the experimental plugin hooks, use tox internals at your own risk.

- DEPRECATE distshare in documentation