6.31 Lab training: Unit tests to evaluate your program
Auto-graded programming assignments may use a Unit test to test small parts of a program. Unlike a Compare output test, which evaluates your program's output for specific input values, a Unit test evaluates individual functions to determines if each function:
* is named correctly and has the correct parameters and return type
* calculates and returns the correct value (or prints the correct output)
The zyLabs auto-grader runs main.py as a script. In main.py, the line if __name__ == '__main__': is used to separate the main code from the functions' code so that each function can be unit tested. Enter statements to be run as the main code under if __name__ == '__main__':. Indent the statements so the statements belong to the if block. Refer to the subsection Importing modules and executing scripts under section Module basics for more information about running a program as a script.
Note: Do not remove if __name__ == '__main__': from the code. Otherwise, the unit tests will fail even though the program produces the correct output.
This example lab uses multiple unit tests to test the kilo_to_pounds() function.
Complete a program that takes a weight in kilograms as input, converts the weight to pounds, and then outputs the weight in pounds. 1 kilogram = 2.204 pounds (lbs).
The program must define the following function:
def kilo_to_pounds(kilos) - take kilos as a parameter, convert kilos from kilograms to pounds, and return the weight in pounds.
Ex: If the input of the program is:
10
10 is passed to kilo_to_pounds() and the output of the program is:
22.040 lbs
The program below has an error in the kilo_to_pounds() function.
1. Try submitting the program for grading (click "Submit mode", then "Submit for grading"). Notice that the first two test cases fail, but the third test case passes. The first test case fails because the program outputs the result from the kilo_to_pounds() function, which has an error. The second test case uses a Unit test to test the kilo_to_pounds() function, which fails.
2. Change the kilo_to_pounds() function to multiply the variable kilos by 2.204, instead of dividing. The return statement should be: return (kilos * 2.204). Submit again. Now the test cases should all pass.
Note: A common error is to mistype a function name with the incorrect capitalization. Function names are case sensitive, so if a lab program asks for a kilo_to_pounds() function, a kilo_To_Pounds() function that works for you in "Develop mode" will result in a failed unit test. The unit test will not be able to find kilo_to_pounds().
6.31.1: Lab training: Unit tests to evaluate your program
main.py
def kilo_to_pounds(kilos):
# This statement intentionally has an error.
return (kilos / 2.204)
# Main part of the program starts here. Do not remove the line below.
if __name__ == '__main__':
