Now that you’ve created the first test, you want to execute it. Sure, you know it’s going to pass, but before you create more complex tests, you should check that you can execute the tests successfully.

Executing Test Runners

The Python application that executes your test code, checks the assertions, and gives you test results in your console is called the test runner. At the bottom of test.py, you added this small snippet of code:

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

This is a command line entry point. It means that if you execute the script alone by running python test.py at the command line, it will call unittest.main(). This executes the test runner by discovering all classes in this file that inherit from unittest.TestCase.

This is one of many ways to execute the unittest test runner. When you have a single test file named test.py, calling python test.py is a great way to get started.

Another way is using the unittest command line. Try this:

$ python -m unittest test

This will execute the same test module (called test) via the command line.

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From realpython.com