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glamouracademy's solution

to Gigasecond in the Ruby Track

Instructions
Test Suite
Solution

Gigasecond

Calculate the moment when someone has lived for 109 seconds.

A gigasecond is 109 (1,000,000,000) seconds.


For installation and learning resources, refer to the exercism help page.

For running the tests provided, you will need the Minitest gem. Open a terminal window and run the following command to install minitest:

gem install minitest

If you would like color output, you can require 'minitest/pride' in the test file, or note the alternative instruction, below, for running the test file.

Run the tests from the exercise directory using the following command:

ruby gigasecond_test.rb

To include color from the command line:

ruby -r minitest/pride gigasecond_test.rb

Source

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.

gigasecond_test.rb

require 'minitest/autorun'
require_relative 'gigasecond'

# Common test data version: 1.0.0 61e7d70
class GigasecondTest < Minitest::Test
  def test_date_only_specification_of_time
    # skip
    assert_equal Time.utc(2043, 1, 1, 1, 46, 40), Gigasecond.from(Time.utc(2011, 4, 25, 0, 0, 0))
  end

  def test_second_test_for_date_only_specification_of_time
    skip
    assert_equal Time.utc(2009, 2, 19, 1, 46, 40), Gigasecond.from(Time.utc(1977, 6, 13, 0, 0, 0))
  end

  def test_third_test_for_date_only_specification_of_time
    skip
    assert_equal Time.utc(1991, 3, 27, 1, 46, 40), Gigasecond.from(Time.utc(1959, 7, 19, 0, 0, 0))
  end

  def test_full_time_specified
    skip
    assert_equal Time.utc(2046, 10, 2, 23, 46, 40), Gigasecond.from(Time.utc(2015, 1, 24, 22, 0, 0))
  end

  def test_full_time_with_day_roll_over
    skip
    assert_equal Time.utc(2046, 10, 3, 1, 46, 39), Gigasecond.from(Time.utc(2015, 1, 24, 23, 59, 59))
  end

  # Problems in exercism evolve over time, as we find better ways to ask
  # questions.
  # The version number refers to the version of the problem you solved,
  # not your solution.
  #
  # Define a constant named VERSION inside of the top level BookKeeping
  # module, which may be placed near the end of your file.
  #
  # In your file, it will look like this:
  #
  # module BookKeeping
  #   VERSION = 1 # Where the version number matches the one in the test.
  # end
  #
  # If you are curious, read more about constants on RubyDoc:
  # http://ruby-doc.org/docs/ruby-doc-bundle/UsersGuide/rg/constants.html

  def test_bookkeeping
    skip
    assert_equal 6, BookKeeping::VERSION
  end
end
class Gigasecond
	ONE_GIGASECOND = 10**9

	def self.from(date)
		(date.to_time + ONE_GIGASECOND).to_date
	end
end

What can you learn from this solution?

A huge amount can be learnt from reading other people’s code. This is why we wanted to give exercism users the option of making their solutions public.

Here are some questions to help you reflect on this solution and learn the most from it.

  • What compromises have been made?
  • Are there new concepts here that I could read more about to develop my understanding?

Community Comments

See what others have said about this solution
over 3 years ago
glamouracademy says

@sprunger thanks so I tried removing to_time and to_date, thinking that when I added ONE_GIGASECOND to date, ruby might stick with the date convention but this didn't work. Could you elaborate?

here's what didn't work:
(date + ONE_GIGASECOND)

over 3 years ago
sprunger says

Looks good! Did you know that Ruby is pretty good at using convention, meaning you only need to specify unconventional aspects. See what happens when you just add a number to a Date.

over 3 years ago
glamouracademy says

removed require 'time' from test

over 3 years ago
glamouracademy says

didn't need to require 'date' as it was in the test