This PR introduces parts of my standard python development tool chain into ixdat for evaluation. The tools falls into two different categories, "tools" and something which I generally call "tool runners".

Of tools this introduces only pytestas a test runner and flake8 as a linter (takes care of some coding errors and coding style related stuff). flake8 is more or less standard if you want a fast and not too opinionated linter and I have over time come to prefer that over something like pylint. I did not include black to the configuration just yet, as I wanted to see if you are happy with it first.

Tool runners is likely the more interesting category, because those types of tools may not be too well known for scientists. These are tools to run your tools and perform tasks for you. You may ask, "why would I want a tool to run a tool?". The answer is that it can help you remember worthwhile options and in general make sure that it is run in an consistent manner and that tasks are performed easier and consistently.

As tools runners I have introduced invoke (http://www.pyinvoke.org/). The purpose of invoke is to easily make it possible and easy to do all the things/perform all the tasks, you need during development. Whenever you need to do something, you should check if invoke has a task for it and ask it to do it. If you perform a task that invoke hasn't been configured for and you do it more than twice, you should probably just go ahead and define an invoke task for it. In the olden days Unix developers would often use something like makefiles for this (https://en.wikipedia.org/wiki/Makefile), but they don't work on Windows which is the reason something like sphinx has both a makefile and a make bat file to compile the docs. Invoke aims to bridge that gap by providing as much of a platform independent command execution environment available as possible and by making its configuration file a pure python file, which means that you can yourself program your way around the whatever platform difference issues you may run into.

During development invoke commands to commonly use could be something like:

invoke lint

to run the linter

invoke tests

to run the tests

invoke checks

to run all the standard code checks (lint and test for now)

invoke clean

to delete all the temporary and cache files

invoke build-docs

to build the docs (not yet implemented)

to see a list of all available tasks do:

invoke --list

The second tool runner is tox (https://tox.readthedocs.io/en/latest/). tox is a tool to run all your QA tools in as consistent a manner as possible across as many of the supported python version as possible. It runs the QA tools in a virtual environment on a freshly installed version of your code. Because tox is meant mainly for continuous integration environments, it will try and perform all the tests on all the supported python versions. If they are unavailable, it will report an error, for this purpose I have configured an invoke task to run tox only on the python version that are available.

To run tox purely do:

tox

to run in parallel do:

tox -p auto

To run tox only on available python versions do

invoke tox

I tried to gather all the information that developers will needs about the tools in the TOOLS.rst file. Please give that a look.

NOTE: This is WIP since I know it has a directory conflict with #2, which I will resolve here when #2 is merged.

EDIT: I completely forgot to mention that the PR also includes a git hook, which is a mechanism to run tests and checks before pushing commits to a remote branch. Please see the details of it and installation instructions in TOOLS.rst.