Most of the power of testing in Python comes from the unittestframework and it’s TestCase class.
Technically, unittest is Python’s library for writing tests.

TestCase

TestCase is a collection of tests. It is a class that contains multiple methods,
some of which are tests, and others that are just methods that you need.
There are two special methods, Set Up and Tear Down, that are run before and after each test.

Our First Test

Now, unlike doc tests, we’re gonna write all of our tests in a separate file, called test.py.
To write our tests, we’re gonna group our tests into what’s called a test case.
So, we’re gonna make a new class and we’re gonna call this MoveTests, and it’s going to extend unittest.TestCase.

import unittest
import moves

class MoveTests(unittest.TestCase):
    def test_five_plus_five(self):
        assert 5 + 5 == 10
        
    def test_one_plus_one(self):
        assert not 1 + 1 == 3
        

import unittest
The library that let’s you write tests.

import moves
The code we’re actually going to test after trying out these simple math tests.

def test_five_plus_five(self)
All tests in a TestCase have to start with the word test_ to be run.
You can have methods that don’t start with test_ for other purposes if you need them.

assert 5 + 5 == 10
Assert makes sure that whatever comes after it is true.

Running tests

Command Line

python -m unittest tests.py

In a Script

If you want the tests to run automatically when you run the script using python tests.py, add the following lines to the bottom of tests.py.

if __name__ == '__main__':
    unittest.main()

For more information on UnitTests, check its documentation.
https://docs.python.org/3/library/unittest.html