Beginner’s guide to using Codecov with Python and Travis CI
Codecov is a tool that is used to measure the test coverage of your codebase. It generally calculates the coverage ratio by examining which lines of code were executed while running the unit tests.
So, how to integrate it into a python project that would use Travis as its CI service? This is how I did it. I had a project structure something similar to what is shown below.
project_root_folder
|-------- module_folder
| |----- __init__.py
| |----- module.py
|-------- test
|----- __init__.py
|----- test_module.py I was using the test discovery feature to run all the tests automatically at once. This is indeed a great feature of python unittest library and i was using it like,
$ python -m unittest discoverI was doing good with this setup when one day I came across some silly bugs in my project when I started to doubt the test quality of my codebase. Then I stumbled over 2 really great tools, Codecov & Coverage. I will show you how to use it step by step.
Follow along with me from here
- Visit https://codecov.io and Log in with Github/Gitlab/Bitbucket according to where the required repository is stored.
- Then from ‘Add a repository’ button move ahead to select and add the repository which you want to integrate with Codecov.
- If all goes well up to this, you are probably on a page that looks something like this,
4. This is where all the confusion starts. Tokens are more or less always difficult to maintain. But if as long as you are using Travis CI, you need not worry at all.
5. In the install section of your travis.yml file add the line,
pip install coverageNow, you might be guessing what is coverage right? Coverage is the tool that does all the hard work of actually generating the coverage report from your codebase which is then uploaded to Codecov which keeps track of all the metrics and progress reports related to the test coverage.
6. Then in the script section of your Travis config file, change the line
python -m unittest discoverto
coverage run -m unittest discoverThat’s it, coverage will run all the tests and generate the report automatically. You can find the report in the form of a .coverage file, though it's not at all readable.
7. Lastly, in the after_success section of your Travis config file, add the line
bash <(curl -s https://codecov.io/bash)This is a bash uploader developed by Codecov to ease the process of uploading reports from CI service automatically. Since we are on Travis CI, we didn’t need to set any environment variables like CODECOV_TOKEN or such.
8. And that’s it. You can now see the detailed coverage report of your code on your Codecov dashboard. Wasn’t that fun.
Feel free to shoot me up with any doubts or suggestions on how to make this article better. I will be more than happy to help. Thanks a lot for your precious time.
