Bite 359. Implementation of a More Sophisticated Typer Tests

Note this is a Test Bite and uses Python 3.7 and MutPy 0.6.1

Building up on the previous Bite, you now have the chance to dive deeper into writing tests for Typer.

Therefore, write a test that checks whether functionality and help description works for both commands compare and subtract.

Check out the Typer documentation about tests for more information.

Enjoy!

PS: We test your test implementation using mut.py. Because if __name__ == "__main__" confuses the mutation testing, we removed it from the script.py.