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to Gigasecond in the Python Track

Published at Jul 13 2018 · 0 comments
Test suite


This solution was written on an old version of Exercism. The tests below might not correspond to the solution code, and the exercise may have changed since this code was written.

Calculate the moment when someone has lived for 10^9 seconds.

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 the appropriate command below (why they are different):

  • Python 2.7: py.test gigasecond_test.py
  • Python 3.4+: pytest gigasecond_test.py

Alternatively, you can tell Python to run the pytest module (allowing the same command to be used regardless of Python version): 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 the help page.


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.


import unittest
from datetime import datetime

from gigasecond import add_gigasecond

# Tests adapted from `problem-specifications//canonical-data.json` @ v1.1.0

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

    def test_another_date_only_specification_of_time(self):
            add_gigasecond(datetime(1977, 6, 13)),
            datetime(2009, 2, 19, 1, 46, 40))

    def test_one_more_date_only_specification_of_time(self):
            add_gigasecond(datetime(1959, 7, 19)),
            datetime(1991, 3, 27, 1, 46, 40))

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

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

    def test_yourself(self):
        # customize this to test your birthday and find your gigasecond date:
        your_birthday = datetime(1970, 1, 1)
        your_gigasecond = datetime(2001, 9, 9, 1, 46, 40)

        self.assertEqual(add_gigasecond(your_birthday), your_gigasecond)

if __name__ == '__main__':
from datetime import timedelta

def add_gigasecond(birth_date):
    return birth_date + timedelta(0, 1e9)

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