How could I use 'assert' and a variable 'actual' to write a test code for a user input code for the conversion of time?

`

def conversion():
    options = print('Would you like to convert hours to mins, or mins to hours?')
    choice = input()

    if choice == 'hours to mins':
        hours = int(input('How many hours? '))
        mins = hours * 60
        print(mins, 'Minutes')
    elif choice == 'mins to hours':
        mins = int(input('How many minutes? '))
        hours = mins/60
        print(hours, 'Hours')
    else:
        print('An error has occured')
        


conversion()

This is the production code which is meant to be used to write a corresponding test code. `

I am unsure on how to go about writing a test code using ‘siminput’ ‘assert’ and the a variable ‘actual’ to write a working test code for the line of code above for it to properly run in unittest.

>Solution :

You can use pytest with the pytest-mock extension. Install them via pip or conda, or whatever you use.

Quick Fix

First I made a small change to your code to make it a bit easier to test: I added a return statement. Now the code will also return the result.

# conversion.py
def conversion():
    print('Would you like to convert hours to mins, or mins to hours?')
    choice = input()

    if choice == 'hours to mins':
        hours = int(input('How many hours? '))
        mins = hours * 60
        print(mins, 'Minutes')
        return mins
    elif choice == 'mins to hours':
        mins = int(input('How many minutes? '))
        hours = mins/60
        print(hours, 'Hours')
        return hours
    else:
        print('An error has occured')
        return False

Ok, now we create a test

# conversion_test.py
def test_hrs_to_min(mocker):
    input_provider = mocker.patch('builtins.input')
    # This line is crucial: You configer the values each call to `Input` will return. 
    input_provider.side_effect = ['hours to mins', '3']
    result = conversion()
    assert result == 3*60

when we run this now with pytest -s from the comannd line, we see the result.
You can also mock the builtin.print and check if it was called with the right arguments (mock_print.assert_called_with(3*60, "Minutes").

See Mocking examples for further details.

Better Solution

As already meantioned it’d be a good idea to sepereate concerns in your code.

def conversion():
    print('Would you like to convert hours to mins, or mins to hours?')
    choice = input()
    if choice == 'hours to mins':
        hours = int(input('How many hours? '))
        print(hrs2mins(hours), 'Minutes')
    elif choice == 'mins to hours':
        mins = int(input('How many minutes? '))
        print(min2hrs(mins), 'Hours')

    print('An error has occured')
    return False


def hrs2mins(hrs: int) -> int:
    return hrs * 60


def min2hrs(mins: int) -> float:
    return mins/60

now you can test the "business logic" (the conversion) seperatly from the User interface…