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to Gigasecond in the Python Track

Published at May 06 2021 · 0 comments
Test suite

Given a moment, determine the moment that would be after a gigasecond has passed.

A gigasecond is 10^9 (1,000,000,000) seconds.

Exception messages

Sometimes it is necessary to raise an exception. When you do this, you should include a meaningful error message to indicate what the source of the error is. This makes your code more readable and helps significantly with debugging. Not every exercise will require you to raise an exception, but for those that do, the tests will only pass if you include a message.

To raise a message with an exception, just write it as an argument to the exception type. For example, instead of raise Exception, you should write:

raise Exception("Meaningful message indicating the source of the error")

Running the tests

To run the tests, run pytest gigasecond_test.py

Alternatively, you can tell Python to run the pytest module: python -m pytest gigasecond_test.py

Common pytest options

  • -v : enable verbose output
  • -x : stop running tests on first failure
  • --ff : run failures from previous test before running other test cases

For other options, see python -m pytest -h

Submitting Exercises

Note that, when trying to submit an exercise, make sure the solution is in the $EXERCISM_WORKSPACE/python/gigasecond directory.

You can find your Exercism workspace by running exercism debug and looking for the line that starts with Workspace.

For more detailed information about running tests, code style and linting, please see Running the Tests.


Chapter 9 in Chris Pine's online Learn to Program tutorial. http://pine.fm/LearnToProgram/?Chapter=09

Submitting Incomplete Solutions

It's possible to submit an incomplete solution so you can see how others have completed the exercise.


from datetime import datetime
import unittest

from gigasecond import add

# Tests adapted from `problem-specifications//canonical-data.json`

class GigasecondTest(unittest.TestCase):
    def test_date_only_specification_of_time(self):
            add(datetime(2011, 4, 25, 0, 0)), datetime(2043, 1, 1, 1, 46, 40)

    def test_second_test_for_date_only_specification_of_time(self):
            add(datetime(1977, 6, 13, 0, 0)), datetime(2009, 2, 19, 1, 46, 40)

    def test_third_test_for_date_only_specification_of_time(self):
            add(datetime(1959, 7, 19, 0, 0)), datetime(1991, 3, 27, 1, 46, 40)

    def test_full_time_specified(self):
            add(datetime(2015, 1, 24, 22, 0)), datetime(2046, 10, 2, 23, 46, 40)

    def test_full_time_with_day_roll_over(self):
            add(datetime(2015, 1, 24, 23, 59, 59)), datetime(2046, 10, 3, 1, 46, 39)

if __name__ == "__main__":
from datetime import timedelta, datetime
GIGASECOND = 10 ** 9

def add(moment: datetime) -> datetime:
    return moment + timedelta(seconds=GIGASECOND)

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