Contribute to VHC

How To

The suggested workflow for implementing bug fixes and/or new features is the following:

  • Identify or, if necessary, add to our redmine issue tracker one or more issues to tackle. Multiple issues can be addressed together if they belong together. Assign the issues to yourself.

  • Create a new branch from the trunk with a name either referring to the topic or the issue to solve. E.g. if you need to add a new executable, tracked by issue #1111 do_something:

    svn cp ^/trunk ^/branches/do_something_1111\
-m 'create branch to solve issue #1111'

  • Switch to the branch:

    svn switch ^/branches/do_something_1111

  • Implement the required changes and don’t forget to track your progress on redmine. If the feature/bug fix requires a large amount of time, we suggest, when possible, to avoid one big commit at the end in favour of smaller commits. In this way, in case of breakages, is easier to traverse the branch history and find the offending code. For each commit you should add an entry in the Changelog file.

    If you work on multiple issues on the same branch, close one issue before proceeding to the next. When closing one issue is good habit to add in the description on the redmine the revision that resolves it.

  • Every function or class added or modified should be adequately documented as described in Coding style.

    Documentation is essential both for users and for your fellow developers to understand the scope and signature of functions and classes. If a new module is added, it should be also added to the documentation in the appropriate place. See the existing documentation for examples.

    Each executable should be documented and its description should contain enough information and examples to allow users to easily run it.

  • Every functionality should be thoroughly tested for python 2.7 and 3.4 or 3.5 in order to ensure that the code behaves as expected and that future modifications will not break existing functionalities. When fixing bugs, add tests to ensure that the bug will not repeat. For more information see Testing.

  • Once the issue(s) are solved and the branch is ready, merge any pending change from the trunk:

    svn merge ^/trunk

    While doing the merge, you might be asked to manually resolve one or more conflicts. Once all the conflicts have been solved, commit the changes with a meaningful commit message, e.g.: merge ^/trunk into ^/branches/do_something_1111. Then rerun the test suite to make sure your changes do not break functionalities implemented while you were working on your branch.

  • Then contact the maintainer of pyhetdex and ask to merge your branch back to the trunk.

Information about branching and merging can be found in the svn book. For any questions or if you need support do not hesitate to contact the maintainer or the other developers.

Coding style

All the code should be compliant with the official python style guidelines described in PEP 8. To help you keep the code in spec, we suggest to install plugins that check the code for you, like Synstastic for vim or flycheck for Emacs.

The code should also be thoroughly documented using the numpy style. See the existing documentation for examples.

Testing

Note

Every part of the code should be tested and should run at least under python 2.7 and 3.4 or greater

VHC uses the testing framework provided by the pytest package. The tests should cover every aspect of a function or method. If exceptions are explicitly raised, this should also tested to ensure that the implementation behaves as expected.

The preferred way to run the tests is using tox, an automatised test help package. If you have installed tox, with e.g. pip install tox, you can run it by typing:

tox

It will take care of creating virtual environments for every supported version of python, if it exists on the system, install vhc, its dependences and the packages necessary to run the tests and runs py.test

You can run the tests for a specific python version using:

py.test

or:

python setup.py test

The latter command fetches all the needed dependences, among others pytest itself, and install them in a .eggs directory. Then it will run py.test. This command might fail when running in a virtual environment. If you get ImportError: No module named 'numpy' while installing scipy, install numpy by hand pip install [--user] numpy and rerun it again. Use the option --addopts to pass additional options to py.test.

You can run specific tests providing the file name(s) and, optionally the name of a test. E.g.:

py.test tests/test_config.py  # test only the configuration module
py.test tests/test_config.py::test_global_conf  # run only one function

Relevant command line options:

-v                    verbose output: print the names and parameters of the
                      tests
-s                    capture standard output: can cause weird interactions
                      with the logging module

Integration tests are marked as such and can be run alone or disabled running either one of the following commands:

py.test -m "not integration"  # exclude intergration tests
py.test -m integration  # run only integration tests

or:

tox -- "-m 'not integration'"  # exclude intergration tests
tox -- "-m integration"  # run only integration tests

A code coverage report is also created thanks to the pytest-cov plugin and can be visualized opening into a browser cover/index.html. If you want a recap of the coverage directly in the terminal you can provide one of the following options when running py.test:

--cov-report term
--cov-report term-missing

Besides running the tests, the tox command also builds, by default, the documentation and collates the coverage tests from the various python interpreters and can copy then to some directory. To do the latter create, if necessary, the configuration file ~/.config/little_deploy.cfg and add to it a section called vhc with either one or both of the following options:

[vhc]
# if given the deploys the documentation to the given dir
doc = /path/to/dir
# if given the deploys the coverage report to the given dir
cover = /path/to/other/dir

# it's also possible to insert the project name and the type of the document
# to deploy using the {project} and {type_} placeholders. E.g
# cover = /path/to/dir/{project}_{type_}
# will be expanded to /path/to/dir/vhc_cover

For more information about the configuration file check little_deploy.

For other command line arguments type:

py.test -h

For a list of available fixtures type:

py.test --fixtures tests/

Documentation

To build the documentation you need the additional dependences described in Optional dependences. They can be installed by hand or during vhc installation executing one of the following commands on a local copy:

pip install /path/to/vhc[doc]
pip install /path/to/vhc[livedoc]

The first install sphinx, the alabaster theme and the numpydoc extension; the second also sphinx-autobuild.

To build the documentation in html format go to the doc directory and run:

make html

The output is saved in doc/build/html. For the full list of available targets.

If you are updating the documentation and want avoid the edit-compile-browser refresh cycle, and you have installed sphinx-autobuild, type:

make livehtml

This command compiles the documentation and serves it on http://127.0.0.1:{port}, where {port} is an available port, and open the page on your default browser. The html documentation is automatically rebuilt after every change of the source and the browser reloaded.