Testing the Server

The server part of Isso is tested by the pytest tool. You should also install the coverage module with the pytest-cov plugin to receive code coverage statistics.

(.venv) $ pip install pytest pytest-cov coverage

Run Isso’s standard server test suite:

(.venv) make test

You can also run tests independently via pytest [options] isso/tests/.


Improvements to Isso’s test coverage and/or different testing strategies are always welcome! Please see the Contribute page for further information.

Check Python code style using flake8:

(.venv) $ pip install flake8
(.venv) $ make flakes

Generate and view server test coverage:

(.venv) $ make coverage


The Continuous Integration suite running via GitHub Actions will throw an error if either the unit tests, the integration tests or the flake8 tests fail or the code coverage falls below 70%.

DistributionNotFound error

Pytest needs your Isso package to be visible in its PATH to work, else it will complain with:

pkg_resources.DistributionNotFound: The 'isso' distribution was not found and is required by the application

When running pytest directly, you need to be aware that it will prioritize the packaged version of Isso in your site-packages, not the one you have in your current working directory.

That is why you should uninstall the pip package of Isso and set PYTHONPATH=. before running tests. The project Makefile already does the latter for you.

Alternatively, use pip install -e . to install Isso as an “editable” package (the package in site-packages will be a symlink to your current development directory).


This section of the Isso documentation is incomplete. Please help by expanding it.

Click the Edit on GitHub button in the top right corner and read the GitHub Issue named Improve & Expand Documentation for further information.

What’s missing?

  • Maybe some links to “how to write good python tests”

… and other things about server testing that should be documented.