Python Testing with pytest

Using coverage.py with pytest-cov

Both coverage.py and pytest-cov are third-party packages that need to be installed before use:

$ pip install coverage
$ pip install pytest-cov

To run tests with coverage.py, you need to add the --cov flag and provide either a path to the code you want to measure, or the installed package you are testing. In our case, the Cards project is an installed package, so we’ll test it using --cov=cards.

The normal pytest output is followed by the coverage report, as shown here:

$ cd /path/to/code
$ pytest --cov=cards ch7
============================ test session starts =============================
collected 27 items

ch7/test_add.py .....                                                  [ 18%]
ch7/test_config.py ...