Use the function in the module

Before we start writing an "automated test", let's see how one could test this code "manually". In reality I see this many times. I see people write short snippets of code to check if their real code works properly, but they don't turn these small snippets into real tests. They don't add them to version control and they don't set up a Continuous Integration (CI) system that would run all the tests on every push to GitHub or GitLab.

Basically the question is "How can we use the add function of the mymath module?"

The code using the module is straight forward. We import the mymath module. We also import the sys module to be able to access the command line arguments. We take two arguments from the command line, call the add function, and print the result.

Then, if we would like to make sure our code works well, we can compare that result to the expected result we calculated in our head.

We try to see if 2+2=4. Based on this everything works fine.

The use_mymath.py file:

import mymath
import sys

if len(sys.argv) != 3:
    exit(f"Usage {sys.argv[0]} NUMBER NUMBER")

a = int(sys.argv[1])
b = int(sys.argv[2])

result = mymath.add(a, b)

print(result)

Usage:

python use_mymath.py 2 2
4