Can someone help me to get unit testing for get_net?

Question

I was able to unit test get_gross and get_tax but what is the command to unit test get_net from the code below.

https://code.sololearn.com/c9D4Tws696D0/?ref=app

What is the code to write unit test for get_net.

Below is the unit test.
https://code.sololearn.com/cmlbKWmoNj6k/?ref=app