Setting up unit tests for devolearn was actually the first time that I was ever touching those testing libraries. While setting up the tests, this came to be the most useful resource I found.

Why do we even need tests ?

It is safe to assume that one day more contributors would come to devolearn. When a future contributor makes a pull request, these tests would make sure that the pull requests are not breaking the code, and the tests would work as an early warning system if a pull request does break the code.

In our case, we used travis CI to run our tests online after each push/pull request. For this we had to set up a .travis.yml file on the same diirectory as the setup.py.

A .travis.yml file looks like:

language: python
python:
  - "3.7"
  - "3.8"

dist: bionic

install: 
  - pip install .
  - pip install -r requirements.txt
script:  
  - python setup.py test

I will break down the file bit by bit:

  • language: python : Because we’ll be running the tests on python.

  • python: This section specifies the versions of python on which we’ll be running the tests.

  • install: Specifies the terminal commands one would need to run in order to install the required libraries.

  • script: Specifies the terminal command(s) needed to run the test(s).

On top of that, I had to add this to the setup() function in setup.py:

test_suite='nose.collector',
tests_require=['nose']

And as for the test functions themselves, the were pretty easy to set up. It was as simple as calling all the functions within a subclass of unittest.TestCase. One of the tests in the devolearn unit tests looks like as follows:

centroid_df = segmentor.predict_from_video(<args>)

self.assertTrue(isinstance(centroid_df, pd.DataFrame), "should be a pandas.DataFrame")

The snippet above makes sure that the object returned from the function predict_from_video() is a pandas.DataFrame. If something ever breaks in between, then this test would fail with the message in the 2nd arg of self.assertTrue.

After about an hour worth of errors and debugging, I was finally able to make this weird flex on the readme.