Unit Testing with Pytest

The distill package uses pytest as a means to validate our functions. Below we describe how to run these tests:

Running Unit Tests

Unit tests can be run through the command line, provided that pytest is installed on your machine. If pytest is not installed, it can be installed with the following command:

pip install pytest

Once pytest is installed, you can navigate to the tests directory and begin running unit tests using the following commands:

cd tests
export PYTHONPATH=../
pytest

Note that we must set the PYTHONPATH environment variable to the top level distill directory (or ../ in this case). This ensures that pytest knows where to look for the distill package.

Common Issues

The most common issues when running the unit tests with pytest are that the PYTHONPATH is set incorrectly (or not set at all) or that modules needed to run the tests are not installed on your machine.

To solve these issues, make sure that the PYTHONPATH is set to the proper directory prior to running pytest and install any modules that pytest describes as missing (the missing modules should be explained in the error messages).

Test Coverage

Pytest can also be used to determine test coverage statistics. This can be done by installing the pytest-cov plugin.

pip install pytest-cov

Once this is installed, coverage statistics on the distill package can be obtained through the following commands:

cd tests
export PYTHONPATH=../
pytest --cov=distill ./