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lujanfernaud's solution

to Scrabble Score in the Ruby Track

Published at Mar 27 2019 · 0 comments
Instructions
Test suite
Solution

Given a word, compute the scrabble score for that word.

Letter Values

You'll need these:

Letter                           Value
A, E, I, O, U, L, N, R, S, T       1
D, G                               2
B, C, M, P                         3
F, H, V, W, Y                      4
K                                  5
J, X                               8
Q, Z                               10

Examples

"cabbage" should be scored as worth 14 points:

  • 3 points for C
  • 1 point for A, twice
  • 3 points for B, twice
  • 2 points for G
  • 1 point for E

And to total:

  • 3 + 2*1 + 2*3 + 2 + 1
  • = 3 + 2 + 6 + 3
  • = 5 + 9
  • = 14

Extensions

  • You can play a double or a triple letter.
  • You can play a double or a triple word.

For installation and learning resources, refer to the Ruby resources 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 scrabble_score_test.rb

To include color from the command line:

ruby -r minitest/pride scrabble_score_test.rb

Source

Inspired by the Extreme Startup game https://github.com/rchatley/extreme_startup

Submitting Incomplete Solutions

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

scrabble_score_test.rb

require 'minitest/autorun'
require_relative 'scrabble_score'

class ScrabbleTest < Minitest::Test
  def test_empty_word_scores_zero
    assert_equal 0, Scrabble.new('').score
  end

  def test_whitespace_scores_zero
    skip
    assert_equal 0, Scrabble.new(" \t\n").score
  end

  def test_nil_scores_zero
    skip
    assert_equal 0, Scrabble.new(nil).score
  end

  def test_scores_very_short_word
    skip
    assert_equal 1, Scrabble.new('a').score
  end

  def test_scores_other_very_short_word
    skip
    assert_equal 4, Scrabble.new('f').score
  end

  def test_simple_word_scores_the_number_of_letters
    skip
    assert_equal 6, Scrabble.new('street').score
  end

  def test_complicated_word_scores_more
    skip
    assert_equal 22, Scrabble.new('quirky').score
  end

  def test_scores_are_case_insensitive
    skip
    assert_equal 41, Scrabble.new('OXYPHENBUTAZONE').score
  end

  def test_convenient_scoring
    skip
    assert_equal 13, Scrabble.score('alacrity')
  end
end

scrabble_score.rb

class Scrabble
  SCORES = {
    1  => %w[A E I O U L N R S T],
    2  => %w[D G],
    3  => %w[B C M P],
    4  => %w[F H V W Y],
    5  => %w[K],
    8  => %w[J X],
    10 => %w[Q Z]
  }

  def self.score(word)
    new(word).score
  end

  def initialize(word)
    @word = word || ""
  end

  def score
    letters.sum(&method(:to_score))
  end

  private

  def letters
    @word.upcase.scan(/[A-Z]/)
  end

  def to_score(letter)
    SCORES.find { |_key, value| value.include?(letter) }.first
  end
end

scrabble_score_test.rb

require 'minitest/autorun'
require_relative 'scrabble_score'

class ScrabbleTest < Minitest::Test
  def test_empty_word_scores_zero
    assert_equal 0, Scrabble.new('').score
  end

  def test_whitespace_scores_zero
    # skip
    assert_equal 0, Scrabble.new(" \t\n").score
  end

  def test_nil_scores_zero
    # skip
    assert_equal 0, Scrabble.new(nil).score
  end

  def test_scores_very_short_word
    # skip
    assert_equal 1, Scrabble.new('a').score
  end

  def test_scores_other_very_short_word
    # skip
    assert_equal 4, Scrabble.new('f').score
  end

  def test_simple_word_scores_the_number_of_letters
    # skip
    assert_equal 6, Scrabble.new('street').score
  end

  def test_complicated_word_scores_more
    # skip
    assert_equal 22, Scrabble.new('quirky').score
  end

  def test_scores_are_case_insensitive
    # skip
    assert_equal 41, Scrabble.new('OXYPHENBUTAZONE').score
  end

  def test_convenient_scoring
    # skip
    assert_equal 13, Scrabble.score('alacrity')
  end

  def test_skips_numbers_and_underscores
    # skip
    assert_equal 13, Scrabble.score('12 ala_crity')
  end
end

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