gigasecond

elixir/gigasecond/.exercism/config.json

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+{
+  "authors": [
+    "rubysolo"
+  ],
+  "contributors": [
+    "andrewsardone",
+    "angelikatyborska",
+    "Cohen-Carlisle",
+    "dalexj",
+    "devonestes",
+    "jinyeow",
+    "lpil",
+    "neenjaw",
+    "parkerl",
+    "petehuang",
+    "sotojuan",
+    "Teapane",
+    "waiting-for-dev"
+  ],
+  "files": {
+    "solution": [
+      "lib/gigasecond.ex"
+    ],
+    "test": [
+      "test/gigasecond_test.exs"
+    ],
+    "example": [
+      ".meta/example.ex"
+    ]
+  },
+  "blurb": "Given a moment, determine the moment that would be after a gigasecond has passed.",
+  "source": "Chapter 9 in Chris Pine's online Learn to Program tutorial.",
+  "source_url": "https://pine.fm/LearnToProgram/?Chapter=09"
+}

elixir/gigasecond/.exercism/metadata.json

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+{"track":"elixir","exercise":"gigasecond","id":"5a877667e1af4bd5aa468ba8cdfb94aa","url":"https://exercism.org/tracks/elixir/exercises/gigasecond","handle":"negrienko","is_requester":true,"auto_approve":false}

elixir/gigasecond/.formatter.exs

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+# Used by "mix format"
+[
+  inputs: ["{mix,.formatter}.exs", "{config,lib,test}/**/*.{ex,exs}"]
+]

elixir/gigasecond/.gitignore

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+# The directory Mix will write compiled artifacts to.
+/_build/
+
+# If you run "mix test --cover", coverage assets end up here.
+/cover/
+
+# The directory Mix downloads your dependencies sources to.
+/deps/
+
+# Where third-party dependencies like ExDoc output generated docs.
+/doc/
+
+# Ignore .fetch files in case you like to edit your project deps locally.
+/.fetch
+
+# If the VM crashes, it generates a dump, let's ignore it too.
+erl_crash.dump
+
+# Also ignore archive artifacts (built via "mix archive.build").
+*.ez
+
+# Ignore package tarball (built via "mix hex.build").
+gigasecond-*.tar
+

elixir/gigasecond/HELP.md

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+# Help
+
+## Running the tests
+
+From the terminal, change to the base directory of the exercise then execute the tests with:
+
+```bash
+$ mix test
+```
+
+This will execute the test file found in the `test` subfolder -- a file ending in `_test.exs`
+
+Documentation:
+
+* [`mix test` - Elixir's test execution tool](https://hexdocs.pm/mix/Mix.Tasks.Test.html)
+* [`ExUnit` - Elixir's unit test library](https://hexdocs.pm/ex_unit/ExUnit.html)
+
+## Pending tests
+
+In test suites of practice exercises, all but the first test have been tagged to be skipped.
+
+Once you get a test passing, you can unskip the next one by commenting out the relevant `@tag :pending` with a `#` symbol.
+
+For example:
+
+```elixir
+# @tag :pending
+test "shouting" do
+  assert Bob.hey("WATCH OUT!") == "Whoa, chill out!"
+end
+```
+
+If you wish to run all tests at once, you can include all skipped test by using the `--include` flag on the `mix test` command:
+
+```bash
+$ mix test --include pending
+```
+
+Or, you can enable all the tests by commenting out the `ExUnit.configure` line in the file `test/test_helper.exs`.
+
+```elixir
+# ExUnit.configure(exclude: :pending, trace: true)
+```
+
+## Useful `mix test` options
+
+* `test/<FILE>.exs:LINENUM` - runs only a single test, the test from `<FILE>.exs` whose definition is on line `LINENUM`
+* `--failed` - runs only tests that failed the last time they ran
+* `--max-failures` - the suite stops evaluating tests when this number of test failures
+is reached
+* `--seed 0` - disables randomization so the tests in a single file will always be ran
+in the same order they were defined in
+
+## Submitting your solution
+
+You can submit your solution using the `exercism submit lib/gigasecond.ex` command.
+This command will upload your solution to the Exercism website and print the solution page's URL.
+
+It's possible to submit an incomplete solution which allows you to:
+
+- See how others have completed the exercise
+- Request help from a mentor
+
+## Need to get help?
+
+If you'd like help solving the exercise, check the following pages:
+
+- The [Elixir track's documentation](https://exercism.org/docs/tracks/elixir)
+- The [Elixir track's programming category on the forum](https://forum.exercism.org/c/programming/elixir)
+- [Exercism's programming category on the forum](https://forum.exercism.org/c/programming/5)
+- The [Frequently Asked Questions](https://exercism.org/docs/using/faqs)
+
+Should those resources not suffice, you could submit your (incomplete) solution to request mentoring.
+
+If you're stuck on something, it may help to look at some of the [available resources](https://exercism.org/docs/tracks/elixir/resources) out there where answers might be found.

elixir/gigasecond/README.md

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+# Gigasecond
+
+Welcome to Gigasecond on Exercism's Elixir Track.
+If you need help running the tests or submitting your code, check out `HELP.md`.
+
+## Introduction
+
+The way we measure time is kind of messy.
+We have 60 seconds in a minute, and 60 minutes in an hour.
+This comes from ancient Babylon, where they used 60 as the basis for their number system.
+We have 24 hours in a day, 7 days in a week, and how many days in a month?
+Well, for days in a month it depends not only on which month it is, but also on what type of calendar is used in the country you live in.
+
+What if, instead, we only use seconds to express time intervals?
+Then we can use metric system prefixes for writing large numbers of seconds in more easily comprehensible quantities.
+
+- A food recipe might explain that you need to let the brownies cook in the oven for two kiloseconds (that's two thousand seconds).
+- Perhaps you and your family would travel to somewhere exotic for two megaseconds (that's two million seconds).
+- And if you and your spouse were married for _a thousand million_ seconds, you would celebrate your one gigasecond anniversary.
+
+~~~~exercism/note
+If we ever colonize Mars or some other planet, measuring time is going to get even messier.
+If someone says "year" do they mean a year on Earth or a year on Mars?
+
+The idea for this exercise came from the science fiction novel ["A Deepness in the Sky"][vinge-novel] by author Vernor Vinge.
+In it the author uses the metric system as the basis for time measurements.
+
+[vinge-novel]: https://www.tor.com/2017/08/03/science-fiction-with-something-for-everyone-a-deepness-in-the-sky-by-vernor-vinge/
+~~~~
+
+## Instructions
+
+Your task is to determine the date and time one gigasecond after a certain date.
+
+A gigasecond is one thousand million seconds.
+That is a one with nine zeros after it.
+
+If you were born on _January 24th, 2015 at 22:00 (10:00:00pm)_, then you would be a gigasecond old on _October 2nd, 2046 at 23:46:40 (11:46:40pm)_.
+
+## Source
+
+### Created by
+
+- @rubysolo
+
+### Contributed to by
+
+- @andrewsardone
+- @angelikatyborska
+- @Cohen-Carlisle
+- @dalexj
+- @devonestes
+- @jinyeow
+- @lpil
+- @neenjaw
+- @parkerl
+- @petehuang
+- @sotojuan
+- @Teapane
+- @waiting-for-dev
+
+### Based on
+
+Chapter 9 in Chris Pine's online Learn to Program tutorial. - https://pine.fm/LearnToProgram/?Chapter=09

elixir/gigasecond/lib/gigasecond.ex

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+defmodule Gigasecond do
+  @gigasecond 1_000_000_000
+
+  @doc """
+  Calculate a date one billion seconds after an input date.
+  """
+  @spec from({{pos_integer, pos_integer, pos_integer}, {pos_integer, pos_integer, pos_integer}}) ::
+          {{pos_integer, pos_integer, pos_integer}, {pos_integer, pos_integer, pos_integer}}
+  def from({{_year, _month, _day}, {_hours, _minutes, _seconds}} = erl_date_time) do
+    {:ok, from} =
+      NaiveDateTime.from_erl(erl_date_time)
+
+    from
+    |> NaiveDateTime.add(@gigasecond, :second)
+    |> NaiveDateTime.to_erl()
+  end
+end

elixir/gigasecond/mix.exs

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+defmodule Gigasecond.MixProject do
+  use Mix.Project
+
+  def project do
+    [
+      app: :gigasecond,
+      version: "0.1.0",
+      # elixir: "~> 1.8",
+      start_permanent: Mix.env() == :prod,
+      deps: deps()
+    ]
+  end
+
+  # Run "mix help compile.app" to learn about applications.
+  def application do
+    [
+      extra_applications: [:logger]
+    ]
+  end
+
+  # Run "mix help deps" to learn about dependencies.
+  defp deps do
+    [
+      # {:dep_from_hexpm, "~> 0.3.0"},
+      # {:dep_from_git, git: "https://github.com/elixir-lang/my_dep.git", tag: "0.1.0"}
+    ]
+  end
+end

elixir/gigasecond/test/gigasecond_test.exs

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+defmodule GigasecondTest do
+  use ExUnit.Case
+
+  test "from 2011-04-25 00:00:00" do
+    assert Gigasecond.from({{2011, 4, 25}, {0, 0, 0}}) == {{2043, 1, 1}, {1, 46, 40}}
+  end
+
+  test "from 1977-06-13 00:00:00" do
+    assert Gigasecond.from({{1977, 6, 13}, {0, 0, 0}}) == {{2009, 2, 19}, {1, 46, 40}}
+  end
+
+  test "from 1959-19-07 00:00:00" do
+    assert Gigasecond.from({{1959, 7, 19}, {0, 0, 0}}) == {{1991, 3, 27}, {1, 46, 40}}
+  end
+
+  test "from 2015-01-24 22:00:00" do
+    assert Gigasecond.from({{2015, 1, 24}, {22, 0, 0}}) == {{2046, 10, 2}, {23, 46, 40}}
+  end
+
+  test "from 2015-01-24 23:59:59" do
+    assert Gigasecond.from({{2015, 1, 24}, {23, 59, 59}}) == {{2046, 10, 3}, {1, 46, 39}}
+  end
+
+  @tag :pending
+  test "yourself" do
+    # customize these values for yourself
+    # your_birthday = {{year1, month1, day1}, {0, 0, 0}}
+    # assert Gigasecond.from(your_birthday) == {{year2, month2, day2}, {hours, minutes, seconds}}
+  end
+end

elixir/gigasecond/test/test_helper.exs

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+ExUnit.start()
+ExUnit.configure(exclude: :pending, trace: true)