Simple starter for a String Calculator kata (first 3 steps done)

main.py

# This is a simple starter for a String Calculator kata (https://osherove.com/tdd-kata-1/)
# The following link could be useful for working with the input string:
# https://developers.google.com/edu/python/strings

def add(numbers):
    # Here, write the actual implementation.
    # Don't forget to commit your changes, at least every time you solve a step.
    # Also, don't be afraid to modify any of the existing code. Refactoring is your friend - as the complexity of
    # the program grows, the readability of the code is crucial for future maintainability.

    numbers = numbers.replace("\n", ',')
    numbers_list_as_string = numbers.split(",")
    integers = [int(num) for num in numbers_list_as_string if num.isdigit()]

    return sum(integers)


if __name__ == '__main__':
    inputs = {
        # the dictionary of tested inputs and their expected outputs
        # for empty string ("") we expect the output to be 0
        "": 0,
        "1": 1,
        "1,2": 3,
        "9,2,4,7": 22,
        "1\n2,3": 6,
    }

    for sample in inputs:
        # cycle through all defined samples and call the add method for each of them
        result = add(sample)

        if result == inputs[sample]:
            print(f"✅ Method add for input {sample} correctly returned {result}")
        else:
            print(f"❌ Method add for input {sample!r} returned {result!r}, but the expected result was {inputs[sample]!r}")