147: Testing Single File Python Applications/Scripts with pytest and coverage

03/06/21 • 11 min

Have you ever written a single file Python application or script?
Have you written tests for it?
Do you check code coverage?

This is the topic of this weeks episode, spurred on by a listener question.

The questions:

For single file scripts, I'd like to have the test code included right there in the file. Can I do that with pytest?
If I can, can I use code coverage on it?

The example code discussed in the episode: script.py

def foo(): return 5 def main(): x = foo() print(x) if __name__ == '__main__': # pragma: no cover main() ## test code # To test: # pip install pytest # pytest script.py # To test with coverage: # put this file (script.py) in a directory by itself, say foo # then from the parent directory of foo: # pip install pytest-cov # pytest --cov=foo foo/script.py # To show missing lines # pytest --cov=foo --cov-report=term-missing foo/script.py def test_foo(): assert foo() == 5 def test_main(capsys): main() captured = capsys.readouterr() assert captured.out == "5\n"

Suggestion by @cfbolz if you need to import pytest:

if __name__ == '__main__': # pragma: no cover main() else: import pytest

Sponsored by:

The Complete pytest course is now a bundle, with each part available separately.
- pytest Primary Power teaches the super powers of pytest that you need to learn to use pytest effectively.
- Using pytest with Projects has lots of "when you need it" sections like debugging failed tests, mocking, testing strategy, and CI
- Then pytest Booster Rockets can help with advanced parametrization and building plugins.
Whether you need to get started with pytest today, or want to power up your pytest skills, PythonTest has a course for you.

★ Support this podcast on Patreon ★

Have you ever written a single file Python application or script?
Have you written tests for it?
Do you check code coverage?

This is the topic of this weeks episode, spurred on by a listener question.

The questions:

For single file scripts, I'd like to have the test code included right there in the file. Can I do that with pytest?
If I can, can I use code coverage on it?

The example code discussed in the episode: script.py

Suggestion by @cfbolz if you need to import pytest:

if __name__ == '__main__': # pragma: no cover main() else: import pytest

Sponsored by:

The Complete pytest course is now a bundle, with each part available separately.
- pytest Primary Power teaches the super powers of pytest that you need to learn to use pytest effectively.
- Using pytest with Projects has lots of "when you need it" sections like debugging failed tests, mocking, testing strategy, and CI
- Then pytest Booster Rockets can help with advanced parametrization and building plugins.
Whether you need to get started with pytest today, or want to power up your pytest skills, PythonTest has a course for you.

★ Support this podcast on Patreon ★

Previous Episode

146: Automation Tools for Web App and API Development and Maintenance - Michael Kennedy

Building any software, including web apps and APIs requires testing.
There's automated testing, and there's manual testing.

In between that is exploratory testing aided by automation tools.

Michael Kennedy joins the show this week to share some of the tools he uses during development and maintenance.

We talk about tools used for semi-automated exploratory testing.
We also talk about some of the other tools and techniques he uses to keep Talk Python Training, Talk Python, and Python Bytes all up and running smoothly.

We talk about:

Postman
ngrok
sitemap link testing
scripts for manual processes
using failover servers during maintenance, redeployments, etc
gitHub webhooks and scripts to between fail over servers and production during deployments automatically
floating IP addresses
services to monitor your site: StatusCake, BetterUptime
the affect of monitoring on analytics
crash reporting: Rollbar, Sentry
response times
load testing: Locus

Links:

Sponsored by:

The Complete pytest course is now a bundle, with each part available separately.
- pytest Primary Power teaches the super powers of pytest that you need to learn to use pytest effectively.
- Using pytest with Projects has lots of "when you need it" sections like debugging failed tests, mocking, testing strategy, and CI
- Then pytest Booster Rockets can help with advanced parametrization and building plugins.
Whether you need to get started with pytest today, or want to power up your pytest skills, PythonTest has a course for you.

★ Support this podcast on Patreon ★

Next Episode

148: Coverage.py and testing packages

How do you test installed packages using coverage.py?

Also, a couple followups from last week's episode on using coverage for single file applications.

Links:

Sponsored by:

The Complete pytest course is now a bundle, with each part available separately.
- pytest Primary Power teaches the super powers of pytest that you need to learn to use pytest effectively.
- Using pytest with Projects has lots of "when you need it" sections like debugging failed tests, mocking, testing strategy, and CI
- Then pytest Booster Rockets can help with advanced parametrization and building plugins.
Whether you need to get started with pytest today, or want to power up your pytest skills, PythonTest has a course for you.

★ Support this podcast on Patreon ★