Unit Testing/Pytest/Test Output

Create a Python Program

Create the following Python program. Save it as multiply.py

def multiply(x, y):
    result = x * y
    return result


def main():
    multiplicand = float(input("Enter a multiplicand: "))
    multiplier = float(input("Enter a multiplier: "))
    product = multiply(multiplicand, multiplier)
    print(f"The product is: {product}")


if __name__ == "__main__":
    main()

Create a Test Program

Create the following Pytest test program. Save it as test_multiply.py

import multiply

def test_output(capsys):
    input_values = [
        "2",
        "2"
    ]

    def input(prompt=None):
        return input_values.pop(0)

    multiply.input = input
    assert multiply.main() == None
    captured = capsys.readouterr()
    assert captured.out == "The product is: 4.0\n"

Test Success

Test the program by running pytest in a terminal or command prompt in the same folder as the two programs above and observe the results.

pytest

Test Failure

Change the test source code somehow, such as replacing one of the input numeric values with a different value. Test the program by running pytest again and observe the results.

← Test Input

Unit Testing/Pytest

Test Exceptions →