V2: new tox multi-dimensional, platform-specific configuration -------------------------------------------------------------------- .. note:: This is a draft document sketching a to-be-done implementation. It does not fully specify each change yet but should give a good idea of where things are heading. For feedback, mail the testing-in-python mailing list or open a pull request on https://bitbucket.org/hpk42/tox/src/84d8cf3c2a95fefd874f22c8b2d257e94365472f/doc/config-v2.txt?at=default **Abstract**: Adding multi-dimensional configuration, platform-specification and multiple installers to tox.ini. **Target audience**: Developers using or wanting to use tox for testing their python projects. Issues with current tox (1.4) configuration ------------------------------------------------ Tox is used as a tool for creating and managing virtualenv environments and running tests in them. As of tox-1.4 there are some issues frequently coming up with its configuration language: - there is no way to instruct tox to parametrize testenv specifications other than to list all combinations by specifying a ``[testenv:...]`` section for each combination. Examples of real life situations arising from this: * https://github.com/tomchristie/django-rest-framework/blob/b001a146d73348af18cfc4c943d87f2f389349c9/tox.ini * https://bitbucket.org/tabo/django-treebeard/src/93b579395a9c/tox.ini - there is no way to have platform specific settings other than to define specific testenvs and invoke tox with a platform-specific testenv list. - there is no way to specify the platforms against which a project shall successfully run. - tox always uses pip for installing packages currently. This has several issues: - no way to check if installing via easy_install works - no installs of packages with compiled c-extensions (win32 standard) Goals, resolving those issues ------------------------------------ This document discusses a possible solution for each of these issues, namely these goals: - allow to more easily define and run dependency/interpreter variants with testenvs - allow platform-specific settings - allow to specify platforms against which tests should run - allow to run installer-variants (easy_install or pip, xxx) - try to mimick/re-use bash-style syntax to ease learning curve. Example: Generating and selecting variants ---------------------------------------------- Suppose you want to test your package against python2.6, python2.7 and on the windows and linux platforms. Today you would have to write down 2*2 = 4 ``[testenv:*]`` sections and then instruct tox to run a specific list of environments on each platform. With tox-1.X you can directlys specify combinations:: # combination syntax gives 2 * 2 = 4 testenv names # envlist = {py26,py27}-{win,linux} [testenv] deps = pytest platform = win: windows linux: linux basepython = py26: python2.6 py27: python2.7 commands = py.test Let's go through this step by step:: envlist = {py26,py27}-{windows,linux} This is bash-style syntax and will create ``2*2=4`` environment names like this:: py26-windows py26-linux py27-windows py27-linux Our ``[testenv]`` uses a new templating style for the ``platform`` definition:: platform= windows: windows linux: linux These two conditional settings will lead to either ``windows`` or ``linux`` as the platform string. When the test environment is run, its platform string needs to be contained in the string returned from ``platform.platform()``. Otherwise the environment will be skipped. The next configuration item in the ``testenv`` section deals with the python interpreter:: basepython = py26: python2.6 py27: python2.7 This defines a python executable, depending on if ``py26`` or ``py27`` appears in the environment name. The last config item is simply the invocation of the test runner:: commands = py.test Nothing special here :) .. note:: Tox provides good defaults for platform and basepython settings, so the above ini-file can be further reduced:: [tox] envlist = {py26,py27}-{win,linux} [testenv] deps = pytest commands = py.test Voila, this multi-dimensional ``tox.ini`` configuration defines 2*2=4 environments. The new "platform" setting -------------------------------------- A testenv can define a new ``platform`` setting. If its value is not contained in the string obtained from calling ``sys.platform`` the environment will be skipped. Expanding the ``envlist`` setting ---------------------------------------------------------- The new ``envlist`` setting allows to use ``{}`` bash-style expressions. XXX explanation or pointer to bash-docs Templating based on environments names ------------------------------------------------- For a given environment name, all lines in a testenv section which start with "NAME: ..." will be checked for being part in the environment name. If they are part of it, the remainder will be the new line. If they are not part of it, the whole line will be left out. Parts of an environment name are obtained by ``-``-splitting it. Variant specification with [variant:VARNAME] Showing all expanded sections ------------------------------- To help with understanding how the variants will produce section values, you can ask tox to show their expansion with a new option:: $ tox -l [XXX output ommitted for now] Making sure your packages installs with easy_install ------------------------------------------------------ The new "installer" testenv setting allows to specify the tool for installation in a given test environment:: [testenv] installer = easy: easy_install pip: pip If you want to have your package installed with both easy_install and pip, you can list them in your envlist likes this:: [tox] envlist = py[26,27,32]-django[13,14]-[easy,pip] If no installer is specified, ``pip`` will be used. Default settings related to environments names/variants --------------------------------------------------------------- tox comes with predefined settings for certain variants, namely: * ``{easy,pip}`` use easy_install or pip respectively * ``{py24,py25,py26,py27,py31,py32,py33,py34,pypy19]`` use the respective pythonNN or PyPy interpreter * ``{win32,linux,darwin}`` defines the according ``platform``. You can use those in your “envlist” specification without the need to define them yourself. Use more bash-style syntax -------------------------------------- tox leverages bash-style syntax if you specify mintoxversion = 1.4: - $VARNAME or ${...} syntax instead of the older {} substitution. - XXX go through config.txt and see how it would need to be changed Transforming the examples: django-rest ------------------------------------------------ The original `django-rest-framework tox.ini `_ file has 159 lines and a lot of repetition, the new one would +have 20 lines and almost no repetition:: [tox] envlist = {py25,py26,py27}-{django12,django13}{,-example} [testenv] deps= coverage==3.4 unittest-xml-reporting==1.2 Pyyaml==3.10 django12: django==1.2.4 django13: django==1.3.1 # some more deps for running examples example: wsgiref==0.1.2 example: Pygments==1.4 example: httplib2==0.6.0 example: Markdown==2.0.3 commands = !example: python setup.py test example: python examples/runtests.py Note that ``{,-example}`` in the envlist denotes two values, an empty one and a ``example`` one. The empty value means that there are no specific settings and thus no need to define a variant name. Transforming the examples: django-treebeard ------------------------------------------------ Another `tox.ini `_ has 233 lines and runs tests against multiple Postgres and Mysql engines. It also performs backend-specific test commands, passing different command line options to the test script. With the new tox-1.X we not only can do the same with 32 non-repetive configuration lines but we also produce 36 specific testenvs with specific dependencies and test commands:: [tox] envlist = {py24,py25,py26,py27}-{django11,django12,django13}-{nodb,pg,mysql}, docs [testenv:docs] changedir = docs deps = Sphinx Django commands = make clean make html [testenv] deps= coverage pysqlite django11: django==1.1.4 django12: django==1.2.7 django13: django==1.3.1 django14: django==1.4 nodb: pysqlite pg: psycopg2 mysql: MySQL-python commands = nodb: {envpython} runtests.py {posargs} pg: {envpython} runtests.py {posargs} \ --DATABASE_ENGINE=postgresql_psycopg2 \ --DATABASE_USER=postgres {posargs} mysql: {envpython} runtests.py --DATABASE_ENGINE=mysql \ --DATABASE_USER=root {posargs}