Example of a Python Project Euler testing script (commented)

problem_1_test.py

from json import loads
from os import path
from problem_1 import euler_1 as euler_function
# This allows for a bit more portability, rather than changing the name of the function every time I import this file to a new problem, just run euler_function each time.

def main():
  # Get the expected answers and load them into a list
  with open(path.dirname(__file__) + '/problem_1_expected_answers.json','r') as expected_answers_file:
    expected_answers_data = expected_answers_file.read()
    expected_answers = loads(expected_answers_data)

  # Initialise the successful test counter, and create an empty list for the failed tests, so that any failed tests can print their input, expected value and actual value
  successful_tests = 0
  failed_tests = []
  for expected_answer in expected_answers:
    print(f"Input of {expected_answer['input']} should yield {expected_answer['expected_answer']}")
    success = False
    
    # For those unfamiliar with colouring your text in the terminal, this turns it bold (1) and red (31)
    format_character = '\033[1;31m'
    # And when colouring text in the terminal, always use this to finish it off!
    # Remember your mum telling you if you make a funny face it will stay that way? Well here it's actually true.
    closing_format_character = '\033[0m'

    answer = euler_function(expected_answer['input'])
    if answer == expected_answer['expected_answer']:
      successful_tests += 1
      success = True
      format_character = '\033[1;32m' # This makes it green instead of red
    else:
      failed_tests.append({'input':expected_answer['input'],'expected_answer':expected_answer['expected_answer'],'actual_answer':answer})
    print(f"{format_character}Input of {expected_answer['input']} yields {answer}{closing_format_character}")

  # This should also match the number of entries in your JSON. Note to self: add in that check
  total_tests = successful_tests + len(failed_tests)
  
  print(f"\033[1mTotal tests: {total_tests}\033[0m")
  print(f"\033[1;32mSuccessful tests: {successful_tests} ({successful_tests * 100 / total_tests}%)\033[0m")
  if len(failed_tests) > 0:
    print(f"\033[1;31mFailed tests: {len(failed_tests)} ({len(failed_tests) * 100 / total_tests}%)\033[0m")
    for test in failed_tests:
      # This is why failed tests was a list, so that we can try and see what has gone wrong and where
      print(f"\033[1;31mInput of {test['input']} should have yielded {test['expected_answer']} but yields {test['actual_answer']}\033[0m")

if __name__ == '__main__':
  main()