Register to get access to free programming courses with interactive exercises

Testing through documentation Python: Automated testing

Python has built-in testing through documentation in addition to the classic tests. It is an unusual way to write tests, but developers sometimes use it for library functions. In this lesson, we'll study this topic in more detail to learn what such documentation looks like.

Testing through documentation

The idea is pretty simple. We call a function inside the terminal. The call itself and the resulting output are the tests. Then, we add them to the documentation of the function:

# has a function called `reverse()` that reverses a string
# The `-i` flag turns on the interactive mode after module execution
python -i
# ''
# 'telxeH'

After making the necessary calls, we add them to the function description:

def reverse(string):
    """Reverse string

    >>> reverse('')

Sign up

Programming courses for beginners and experienced developers. Start training for free

  • 130 courses, 2000+ hours of theory
  • 1000 practical tasks in a browser
  • 360 000 students
By sending this form, you agree to our Personal Policy and Service Conditions

Our graduates work in companies:

<span class="translation_missing" title="translation missing:">Bookmate</span>
<span class="translation_missing" title="translation missing:">Healthsamurai</span>
<span class="translation_missing" title="translation missing:">Dualboot</span>
<span class="translation_missing" title="translation missing:">Abbyy</span>
Suggested learning programs
Developing web applications with Django
10 months
from scratch
under development
Start at any time

Use Hexlet to the fullest extent!

  • Ask questions about the lesson
  • Test your knowledge in quizzes
  • Practice in your browser
  • Track your progress

Sign up or sign in

By sending this form, you agree to our Personal Policy and Service Conditions
Toto Image

Ask questions if you want to discuss a theory or an exercise. Hexlet Support Team and experienced community members can help find answers and solve a problem.