Thanks for taking the time to contribute to iCount!

Please submit contributions in accordance with the flow explained in the GitHub Guides.

Installation for development

Fork the main iCount git repository.

If you don’t have Git installed on your system, follow these instructions.

Clone your fork (replace <username> with your GitHub account name) and change directory:

git clone<username>/iCount.git
cd iCount

Prepare iCount for development:

pip install -e .[test]


We strongly recommend to install iCount in virtualenv to create an isolated Python environment.

Installing Docker

When working with docker, make sure that the docker-machine has enough memory to run STAR and associated programs, e.g., at least 32 GB RAM and 45 GB disk:

docker-machine create -d virtualbox --virtualbox-memory 32768 --virtualbox-disk-size "46080" default


Other options for VirtualBox are described here.

Building the documentation

Issue these commands to build the documentation:

pip install -e .[docs]
cd docs
make html
open build/html/index.html


Calling makefile ensures that the reference manual for the CLI is updated. It will envoke this command when needed:

iCount man > source/ref_CLI.txt

Python module and CLI living together

iCount package offers a complete set of Python function to analyse iCLIP data, as well as their command line counterparts. Effectively, they (should) offer excactly the same functionality. However, the tools are in continious development and pipelines will change with time… To avoid differences in functionality as well as the duplication of code, tests and documentation, the command line interface (CLI) is generated automatically from Python functions. For this to work, functions (as well as their docstrings and modules where they are defined) should be written by the conventions described in the following sections.

More about automatic CLI generation (how it works, how to expose function in CLI, etc.) can be read in Automated CLI creation.



  • Line length is 119 characters plus newline character.
  • Use ' instead of " character, if possible.

Parameters naming

If the variable is one of the commonly used names, such as cross-link file name or mismatches, the name should be one of those. For a list of these names, check the TODO: link.


Errors should be raised in a descriptive manner - for example if iCount calls an external tool that return a non-zero exit status, an error should be raised.


We follow Numpy format specification for docstrings.

All docstrings of unittest test functions should have three-braces (“”“) in separate lines (or else, docstrings are printed to stdout during test execution). This explains why:

Correct way:

def test_something(self):
    The docstring.

Wrong way:

def test_something(self):
    """The docstring."""

Commit and PR messages

If the core change that commit is introducing originates from module the_module, commit message should be:

the_module: Commit message

If commit is somehow connected with an issue, commit message should reference issue number:

the_module: Commit message, relates to #42, resolves #14

References to PR greatly help when preparing a description of changes in the change log docs/source/revisions.rst.

Logging logic

Logging is used to report the progress of program execution to user. iCount can be used as Python module or as it’s corresponding CLI.

When using iCount as Python module all logging is turned OFF by defult, so no messages will be printed about analysis execution. However, if user wishes, logging can be easily confiugured with functions defined in

If using the CLI, logging to stdout with INFO level is set by defult. This can be configured for each command by using the appropriate command line arguents. Read more about it in Automated CLI creation.


Tests for iCount python package and corresponding CLI.

There are two types of tests: unit and functional (regression) tests. Continuous development testing supported on GitHub is also explained in the corresponding section.

Unit tests

Unit tests are located in top testing directory (iCount/tests/). They follow the standardy philosophy of unit tests (isolation), although this is sometimes violated when testing functions connect to external resources. This is only the case, when the main task of the function under test is to retrieve a resource from the web. Still, all tests should pass in no more than a couple of minutes.

Test can be run by standard unittest call:

# Run all tests:
python -m unittest iCount
# Run only a specific test:
python -m unittest iCount.test_file_name.Test_class.test_name

Alternatively, all test files can be called also like python script:


Functional tests

Are located in subdirectory iCount/tests/functional. They should be executed manually, only at times one wishes to check that current implementation is compatible with earlier versions of iCount. The results are typically stored for future reference. These test may take significant amount of time to complete and are not meant to be run on daily basis.

Continuous development testing

iCount is project in continious development and therefore has central repository on GitHub. There, automatic testing is performed by:

  • Travis - unit, code and documentation stype testing
  • Coverage - enforcing sufficient covergae
  • Codacy - enforcing code quality
  • Scrutinizer - enforcing documentation quality

Tests on Travis are executed by tox. To avoid making multiple pull requests and waiting for Travis to do the checks, tox can run on local machine:

# Run all tox tests
# Run only a single environment (for example unittests in Python 3.7)
tox -e py37

Tox enables to test code against different versions of Python and also perform code-style checks. This is achieved by different environments. Currently, we test three of them:

  • py37 (Python 3.7)
  • py36 (Python 3.6)
  • py35 (Python 3.5)
  • linters (wraps pylint, PEP8/pycodestyle and PEP257/pydocstyle)

For more info check tox.ini and .travis.yml in packyge root directory.

Naming proposition - TODO

The iCount pipeline looks like so: TODO: image

The elements appearing in it are files and analysis:

For each file (type):
  • format specification = FASTA, FASTQ, GTF, BED6, special, custom…
  • one-letter-CLI-abreviation: ‘-r’
  • full CLI name: ‘–reads’
  • naming convention: example for genome file: species.release[.chr1_chr2_chrMT].fa[.gz]
  • is output of which analysis: ?? (should be clear form image?)
  • can be input for which analysis: ?? (should be clear form image?)
The analysis in it are:
  • analysis name (single word?)
  • execution time (O(n^2), O(reads#, genome_size)) some typical estimation
  • inputs, outputs (should be clear form image?)

Preparing a release

First check that twine is installed:

pip install twine

Requirement already satisfied: twine in ...

Pull the latest master to be released:

git checkout master
git pull

Use the utility script docs/ to list all commits that were made from last tagged release:

docs/ > to_edit.rst

Edit to_edit.rst and incorporate a description of most important changes into docs/source/revisions.rst. Use syntax from releases package.

Remove .dev from project’s version in iCount/ file.

Clean build directory:

python clean -a

Remove previous distributions in dist directory:

rm dist/*

Remove previous egg-info directory:

rm -r *.egg-info

Commit changes:

git add docs/source/revisions.rst iCount/
git commit -m "Release <version>"

Test the new version with Tox:

tox -r

Create source distribution:

python sdist

Build wheel:

python bdist_wheel

Upload distribution to PyPI:

twine upload dist/*


It is advisable to test upload onto the test server first:

twine upload --repository-url dist/*

Afterwards, test the installation in a clean python environment:

docker build -t icounttestinstall -f Dockerfile_test .
docker run -t -i icounttestinstall

pip install -i \
--extra-index-url iCount

Tag the new version:

git tag <version>

Push changes to main repository:

git push origin master <version>

Decide how to bump version (to some new value <new-version>) and modify iCount/ Don’t forget to add suffix .dev:


Commit changes:

git add iCount/
git commit -m "Bump version to <new-version>"