Unit Tests


We want to test a unit of code to make sure it does what we expect, i.e.

def test_addition():
    # given
    summands = [3, 2]

    # when
    the_sum = sum(summands)

    # then
    assert the_sum == 5

Main ingredience of a unit test

  • test data

  • the functionality you want to test

  • meaningful assert statements

Code of Conduct

Some things to keep in mind when writing your unit tests.


Do nots

bring your own test data

API calls

temporary files

read test data from files

negative control



focus on your own package