During handling of the above exception, another exception occurred, Pytest giving an error in ValueE-CodePudding

I am a new learner in Python and here I have try-except to catch ValueErrors and conditional statements to catch the same error as well.

import re


def main():
    print(convert(input("Hours: ")))


def convert(s):
    try:
        # matches := re.search(r"^(\d )\:?(. )? to (\d )\:?(. )?$", s)
        if (matches := re.search(r"^(\d )\:?(. )? to (\d )\:?(. )?$", s)) and s.__contains__("AM"):
            matchesGroup1 = matches.group(1)
            matchesGroup2 = matches.group(2).split(" ")
            matchesGroup3 = matches.group(3)
            matchesGroup4 = matches.group(4).split(" ")

            if 0 < int(matches.group(1)) <= 12 and 0 < int(matches.group(3)) <= 12:

                if matchesGroup2[1] == "AM" and matchesGroup4[1] == "PM":
                    if matchesGroup1 == "12" and matchesGroup3 == "12":
                        matchesGroup1 = "00"
                        matchesGroup3 = "12"
                    else:
                        matchesGroup3 = int(matchesGroup3)   12
                        matchesGroup1 = "0"   matchesGroup1
                else:
                    if matchesGroup1 == "12" and matchesGroup3 == "12":
                        matchesGroup3 = "12"
                        matchesGroup1 = "00"
                    else:
                        matchesGroup1 = int(matchesGroup1)   12
                        matchesGroup3 = "0"   matchesGroup3

                if len(matchesGroup2[0]) == 0 and len(matchesGroup4[0]) == 0:
                    matchesGroup2[0]  = "00"
                    matchesGroup4[0]  = "00"
                elif "00" <= matchesGroup2[0] <= "59" and "00" <= matchesGroup4[0] <= "59":
                    pass
                else:
                    raise Exception

                return f"{matchesGroup1}:{matchesGroup2[0]} to {matchesGroup3}:{matchesGroup4[0]}"

        else:
            raise Exception

    except Exception:
        raise ValueError
    except ValueError:
        raise ValueError


if __name__ == "__main__":
    main()

And I am testing it with PyTest with help of assert. But, in the last line Pytest giving working.py:45: Exception, test_working.py:9: and working.py:48: ValueError. Can anyone explain what it's so and how do i fix it?

import pytest
from working import convert

def test_convert():
    assert convert("9 AM to 5 PM") == "09:00 to 17:00"
    assert convert("9:00 AM to 5:00 PM") == "09:00 to 17:00"
    assert convert("10 PM to 8 AM") == "22:00 to 08:00"
    assert convert("10:30 PM to 8:50 AM") == "22:30 to 08:50"
    assert convert("9:00 AM 5:00 PM") == ValueError

CodePudding user response：

Instead of assert convert("9:00 AM 5:00 PM") == ValueError try using the following syntax:

with pytest.raises(ValueError):
    convert("9:00 AM 5:00 PM")

The issue is that you need to tell the testing framework that you expect to raise an error. Otherwise it won't know whether the error it hits was deliberate or not. With the above code, pytest will now raise an error if that code fails to raise an exception. Not only that, it'll also ensure that the exception you were hoping to raise doesn't stop the execution of the rest of your tests.