Developer documentation

Welcome to the developer documentation of qcPy. Unlike the API documentation, this part gives some general background information for developers who want to actively contribute to the project.

Virtual environment

The whole development should take place inside a virtual python environment that should be located outside the project directory.

To create a new virtual python environment, open a terminal and change to a a directory where the virtual environment should reside. Then type something like:

virtualenv qcpy

This will create a virtual environment in the directory “qcpy”. To activate this virtual environment, use:

source qcpy/bin/activate

To deactivate, the command would simply be:


Autoincrementing version numbers

The version number is contained in the file VERSION in the project root directory. To automatically increment the version number with every commit, use a git hook that calls the file bin/ Git hooks reside in the directory .git/hooks. The simplest would be to create a new file pre-commit in this directory with the following content:

bash bin/

Make sure to set it to executable and have a line break (aka: new or empty line) at the end of the file. Otherwise, you man run into trouble, i.e., not having your version number updated automatically with each commit.

Directory layout

The qcPy package follows good practice of the Python community regarding directory layout. As there will be several subpackages available, these reside each in a separate directory containing its own file. All packages/modules reside below the qcpy directory of the project root. The tests directory follows the same structure and contains all the module tests. Generally, the qcPy package should be developed test-driven (test-first) as much as possible.

(This) documentation resides inside the docs directory of the project root. The auto-generated API documentation is in its own directory.

A general overview of the overall package structure:


As you can see, currently three subpackages, namely “datasafe”, “loi”, and “eln”, are supposed to be created. For details of the qcPy project as such, consult its Homepage.

Docstring format

The Docstring format used within the code of the qcPy package is “NumPy”. For convenience, set your IDE accordingly.

For PyCharm, the settings can be found in Preferences > Tools > Python Integrated Tools. Here, you find a section “Docstrings” where you can select the Docstring format from a number of different formats.

Unittests and test driven development

Developing the qcPy code should be done test-driven wherever possible. The tests reside in the tests directory in the respective subpackage directory (see above).

Tests should be written using the Python unittest framework. Make sure that tests are independent of the respective local environment and clean up afterwards (using appropriate teardown methods).