ruby - space-age

ruby/space-age/README.md

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+# Space Age
+
+Given an age in seconds, calculate how old someone would be on:
+
+   - Earth: orbital period 365.25 Earth days, or 31557600 seconds
+   - Mercury: orbital period 0.2408467 Earth years
+   - Venus: orbital period 0.61519726 Earth years
+   - Mars: orbital period 1.8808158 Earth years
+   - Jupiter: orbital period 11.862615 Earth years
+   - Saturn: orbital period 29.447498 Earth years
+   - Uranus: orbital period 84.016846 Earth years
+   - Neptune: orbital period 164.79132 Earth years
+
+So if you were told someone were 1,000,000,000 seconds old, you should
+be able to say that they're 31.69 Earth-years old.
+
+If you're wondering why Pluto didn't make the cut, go watch [this
+youtube video](http://www.youtube.com/watch?v=Z_2gbGXzFbs).
+
+* * * *
+
+For installation and learning resources, refer to the
+[exercism help page](http://exercism.io/languages/ruby).
+
+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 space_age_test.rb
+
+To include color from the command line:
+
+    ruby -r minitest/pride space_age_test.rb
+
+
+## Source
+
+Partially inspired by Chapter 1 in Chris Pine's online Learn to Program tutorial. [http://pine.fm/LearnToProgram/?Chapter=01](http://pine.fm/LearnToProgram/?Chapter=01)
+
+## Submitting Incomplete Solutions
+It's possible to submit an incomplete solution so you can see how others have completed the exercise.

ruby/space-age/space_age.rb

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+# SpaceAge class
+class SpaceAge
+  EARTH_YEAR_IN_SECONDS = 31_557_600
+
+  def initialize(age_in_seconds)
+    @age_in_seconds = age_in_seconds
+  end
+
+  def on_earth
+    @age_in_seconds.to_f / EARTH_YEAR_IN_SECONDS.to_f
+  end
+
+  def on_mercury
+    on_earth / 0.2408467
+  end
+
+  def on_venus
+    on_earth / 0.61519726
+  end
+
+  def on_mars
+    on_earth / 1.8808158
+  end
+
+  def on_jupiter
+    on_earth / 11.862615
+  end
+
+  def on_saturn
+    on_earth / 29.447498
+  end
+
+  def on_uranus
+    on_earth / 84.016846
+  end
+
+  def on_neptune
+    on_earth / 164.79132
+  end
+end

ruby/space-age/space_age_test.rb

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+require 'minitest/autorun'
+require_relative 'space_age'
+
+# Common test data version: 1.1.0 8d4df79
+class SpaceAgeTest < Minitest::Test
+  # assert_in_delta will pass if the difference
+  # between the values being compared is less
+  # than the allowed delta
+  DELTA = 0.01
+
+  def test_age_on_earth
+    # skip
+    age = SpaceAge.new(1_000_000_000)
+    assert_in_delta 31.69, age.on_earth, DELTA
+  end
+
+  def test_age_on_mercury
+    # skip
+    age = SpaceAge.new(2_134_835_688)
+    assert_in_delta 280.88, age.on_mercury, DELTA
+  end
+
+  def test_age_on_venus
+    # skip
+    age = SpaceAge.new(189_839_836)
+    assert_in_delta 9.78, age.on_venus, DELTA
+  end
+
+  def test_age_on_mars
+    # skip
+    age = SpaceAge.new(2_329_871_239)
+    assert_in_delta 39.25, age.on_mars, DELTA
+  end
+
+  def test_age_on_jupiter
+    # skip
+    age = SpaceAge.new(901_876_382)
+    assert_in_delta 2.41, age.on_jupiter, DELTA
+  end
+
+  def test_age_on_saturn
+    # skip
+    age = SpaceAge.new(3_000_000_000)
+    assert_in_delta 3.23, age.on_saturn, DELTA
+  end
+
+  def test_age_on_uranus
+    # skip
+    age = SpaceAge.new(3_210_123_456)
+    assert_in_delta 1.21, age.on_uranus, DELTA
+  end
+
+  def test_age_on_neptune
+    # skip
+    age = SpaceAge.new(8_210_123_456)
+    assert_in_delta 1.58, age.on_neptune, DELTA
+  end
+end