Testing: coverage¶

Coverage.py is a tool for measuring code coverage of Python programs. It monitors your program, noting which parts of the code have been executed, then analyzes the source to identify code that could have been executed but was not.

Coverage measurement is typically used to gauge the effectiveness of tests. It can show which parts of your code are being exercised by tests, and which are not.

For more information visit https://coverage.readthedocs.io/en/coverage-5.3/

Installation¶

$ poetry add coverage --dev

Configuration¶

Add coverage configurations in pyproject.toml

[tool.coverage.run]
branch = true
source = [
    "python_lifecycle_training",
]

[tool.coverage.report]
# Regexes for lines to exclude from consideration
exclude_lines = [
    # Have to re-enable the standard pragma
    "pragma: no cover",

    # Don't complain about missing debug-only code:
    "def __repr__",
    "if self.debug",

    # Don't complain if tests don't hit defensive assertion code:
    "raise AssertionError",
    "raise NotImplementedError",

    # Don't complain if non-runnable code isn't run:
    "if 0:",
    "if __name__ == .__main__.:",

    # Don't complain about fire commands
    "fire.Fire",
]
fail_under = 90
ignore_errors = true

Usage¶

Use coverage run to run your test suite and gather data. However you normally run your test suite, you can run your test runner under coverage. If your test runner command starts with “python”, just replace the initial “python” with “coverage run”.

$ coverage run -m pytest

Use coverage report to report on the results:

$ coverage report -m

For a nicer presentation, use coverage html to get annotated HTML listings detailing missed lines:

$ coverage html
$ chromium htmlcov/index.html

Next Step¶

To move on to the next step commit or stash your changes then checkout to the branch setup/test/pytest-cov

$ git stash
$ git checkout setup/test/pytest-cov

Uninstall¶

$ poetry remove coverage --dev