Outside-In with Aruba/RSpec for SudokuValidator Exercise

.gitignore

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+tmp/

.rspec

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+--color
+--format documentation
+--require spec_helper

Gemfile

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+source 'https://rubygems.org'
+gemspec

Gemfile.lock

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+PATH
+  remote: .
+  specs:
+    sudoku_validator (0.0.1)
+
+GEM
+  remote: https://rubygems.org/
+  specs:
+    aruba (0.5.3)
+      childprocess (>= 0.3.6)
+      cucumber (>= 1.1.1)
+      rspec-expectations (>= 2.7.0)
+    builder (3.2.2)
+    childprocess (0.3.9)
+      ffi (~> 1.0, >= 1.0.11)
+    cucumber (1.3.10)
+      builder (>= 2.1.2)
+      diff-lcs (>= 1.1.3)
+      gherkin (~> 2.12)
+      multi_json (>= 1.7.5, < 2.0)
+      multi_test (>= 0.0.2)
+    diff-lcs (1.2.5)
+    ffi (1.9.3)
+    gherkin (2.12.2)
+      multi_json (~> 1.3)
+    multi_json (1.8.2)
+    multi_test (0.0.2)
+    rake (10.1.0)
+    rspec (2.14.1)
+      rspec-core (~> 2.14.0)
+      rspec-expectations (~> 2.14.0)
+      rspec-mocks (~> 2.14.0)
+    rspec-core (2.14.7)
+    rspec-expectations (2.14.4)
+      diff-lcs (>= 1.1.3, < 2.0)
+    rspec-mocks (2.14.4)
+
+PLATFORMS
+  ruby
+
+DEPENDENCIES
+  aruba
+  rake
+  rspec
+  sudoku_validator!

Rakefile

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+require 'cucumber'
+require 'cucumber/rake/task'
+
+Cucumber::Rake::Task.new(:features) do |t|
+  t.cucumber_opts = "features --format pretty -x"
+  t.fork = false
+end
+
+task :default => :features

bin/sudoku-validator

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+#!/usr/bin/env ruby
+
+require_relative '../lib/sudoku_fileparser'
+require_relative '../lib/sudoku_puzzle'
+require_relative '../lib/sudoku_validator'
+
+exit unless filename = ARGV[0]
+
+filepath = File.expand_path(filename)
+if File.exist?(filepath)
+  parser    = Sudoku::FileParser.new(File.read(filepath))
+  puzzle    = Sudoku::Puzzle.new(parser.parse_rows)
+  validator = Sudoku::Validator.new(puzzle)
+
+  puts validator.status
+  if validator.errors.any?
+    puts "Errors:"
+    validator.errors.each.with_index(1) do |error, index|
+      puts "  #{index}) #{error}"
+    end
+  end
+else
+  puts "Could not find file #{filename}"
+end

features/sudoku_validator.feature

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+Feature: Validating .sudoku files
+
+  Scenario: A valid, complete sudoku
+    When I successfully run `sudoku-validator ./valid_complete.sudoku`
+    Then the output should contain "This sudoku is valid."
+    Then the output should not contain "Errors:"
+
+  Scenario: A valid, incomplete sudoku
+    When I successfully run `sudoku-validator ./valid_incomplete.sudoku`
+    Then the output should contain "This sudoku is valid, but incomplete."
+    Then the output should not contain "Errors:"
+
+  Scenario: An invalid, complete sudoku
+    When I successfully run `sudoku-validator ./invalid_complete.sudoku`
+    Then the output should contain "This sudoku is invalid."
+    Then the output should contain "Column 4 contains a duplicate 8 in squares 2 and 5"
+    Then the output should contain "Column 6 contains a duplicate 2 in squares 1 and 5"
+
+  Scenario: An invalid, incomplete sudoku
+    When I successfully run `sudoku-validator ./invalid_incomplete.sudoku`
+    Then the output should contain "This sudoku is invalid."
+    Then the output should contain "Column 2 contains a duplicate 5 in squares 1 and 7"
+    Then the output should contain "Column 5 contains a duplicate 8 in squares 2 and 7"

features/support/env.rb

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+require 'aruba/cucumber'
+
+Before do
+  @dirs = ["."]
+end

lib/sudoku_fileparser.rb

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+module Sudoku
+  class FileParser
+    def initialize(file = nil)
+      raise(ArgumentError, "A file is required.") if file.nil?
+      @file = file
+    end
+
+    def parse_rows
+      @file.strip.each_line.map do |line|
+        parse_line(line) unless separator?(line)
+      end.compact
+    end
+
+    private
+
+    def parse_line(line)
+      parse_empties(line).split(/[^\d]+/).map(&:to_i)
+    end
+
+    def parse_empties(line)
+      line.gsub(".", "0")
+    end
+
+    def separator?(line)
+      line.start_with?('-')
+    end
+  end
+end

lib/sudoku_puzzle.rb

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+require_relative 'sudoku_unit'
+require 'matrix'
+
+module Sudoku
+  class Puzzle
+    def initialize(rows = [])
+      raise(ArgumentError, "An array of rows is required to create a puzzle.") if rows.empty?
+      @grid = create_grid(rows)
+    end
+
+    def rows
+      Hash[@grid.row_vectors.map.with_index(1) do |row, index|
+        [index, Row[*row]]
+      end]
+    end
+
+    def columns
+      Hash[@grid.column_vectors.map.with_index(1) do |column, index|
+        [index, Column[*column]]
+      end]
+    end
+
+    def boxes
+      Hash[[0, 3, 6].repeated_permutation(2).map.with_index(1) do |(x, y), index|
+        [index, Box[*@grid.minor(x, 3,  y, 3).to_a.flatten]]
+      end]
+    end
+
+    def complete?
+      rows.all? { |index, row| row.complete? }
+    end
+
+    def valid?
+      all_units.all?(&:valid?)
+    end
+
+    def eql?(other)
+      hash == other.hash
+    end
+
+    def hash
+      @grid.hash
+    end
+
+    alias_method :==, :eql?
+
+    private
+
+    def create_grid(input_rows)
+      Matrix[*input_rows]
+    end
+
+    def all_units
+      rows.values + columns.values + boxes.values
+    end
+  end
+end

lib/sudoku_unit.rb

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+module Sudoku
+  class Unit
+    def self.[](*values)
+      new(values)
+    end
+
+    def initialize(values)
+      @squares = values
+    end
+
+    def positions
+      @squares.each.with_index(1).inject ({}) do |h, (number, position)|
+        h.tap { |h| h[number] = h[number] ? [h[number]].flatten << position : position }
+      end
+    end
+
+    def valid?
+      non_empty_squares.uniq.count === non_empty_squares.count
+    end
+
+    def complete?
+      @squares.none?(&:zero?)
+    end
+
+    def eql?(other)
+      self.class == other.class && hash == other.hash
+    end
+
+    def hash
+      @squares.hash
+    end
+
+    alias_method :==, :eql?
+
+    private
+
+    def non_empty_squares
+      @squares.reject(&:zero?)
+    end
+  end
+
+  class Row < Unit
+    def type
+      "Row"
+    end
+  end
+
+  class Column < Unit
+    def type
+      "Column"
+    end
+  end
+
+  class Box < Unit
+    def type
+      "Box"
+    end
+  end
+end

lib/sudoku_validator.rb

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+module Sudoku
+  class Validator
+    attr_reader :puzzle
+
+    def initialize(puzzle = nil)
+      raise(ArgumentError, "A Puzzle is required.") if puzzle.nil?
+      @puzzle = puzzle
+    end
+
+    def status
+      case [puzzle.valid?, puzzle.complete?]
+      when [true, true]  then "This sudoku is valid."
+      when [true, false] then "This sudoku is valid, but incomplete."
+
+      else "This sudoku is invalid."
+      end
+    end
+
+    def errors
+      return [] if puzzle.valid?
+
+      [:rows, :columns, :boxes].map do |message|
+        puzzle.send(message).map do |index, unit|
+          duplicates(unit).map do |number, positions|
+            DuplicateError.new(unit.type, index, number, positions)
+          end
+        end
+      end.flatten
+    end
+
+    private
+
+    def duplicates(unit)
+      unit.positions.select do |number, position|
+        non_empty?(number) && duplicate?(position)
+      end
+    end
+
+    def non_empty?(number)
+      number != 0
+    end
+
+    def duplicate?(position)
+      position.is_a?(Array)
+    end
+  end
+
+  class DuplicateError < Struct.new(:type, :index, :number, :positions)
+    def to_s
+      "#{type} #{index} contains a duplicate #{number} in squares #{list(positions)}"
+    end
+
+    private
+
+    def list(positions)
+      "#{positions[0...-1].join(', ')} and #{positions.last}"
+    end
+  end
+end

spec/lib/sudoku_fileparser_spec.rb

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+require 'sudoku_fileparser'
+
+module Sudoku
+  describe FileParser do
+    it "throws an ArgumentError if instantiated without a file" do
+      expect { FileParser.new }.to raise_error(ArgumentError)
+    end
+
+    it "can parse rows out of the file into a simple array format (strings are converted to numbers)" do
+      parser = FileParser.new(example_file)
+      parser.parse_rows.should eq [
+        [0, 5, 9, 6, 1, 2, 4, 3, 0],
+        [7, 0, 3, 8, 5, 4, 1, 0, 9],
+        [1, 6, 0, 3, 7, 9, 0, 2, 8],
+        [9, 8, 6, 0, 4, 0, 3, 5, 2],
+        [3, 7, 5, 2, 0, 8, 9, 1, 4],
+        [2, 4, 1, 0, 9, 0, 7, 8, 6],
+        [4, 3, 0, 9, 8, 1, 0, 7, 5],
+        [6, 0, 7, 4, 2, 5, 8, 0, 3],
+        [0, 9, 8, 7, 3, 6, 2, 4, 0]
+      ]
+    end
+
+    def example_file
+    %Q{
+. 5 9 |6 1 2 |4 3 . 
+7 . 3 |8 5 4 |1 . 9 
+1 6 . |3 7 9 |. 2 8 
+------+------+------
+9 8 6 |. 4 . |3 5 2 
+3 7 5 |2 . 8 |9 1 4 
+2 4 1 |. 9 . |7 8 6 
+------+------+------
+4 3 . |9 8 1 |. 7 5 
+6 . 7 |4 2 5 |8 . 3 
+. 9 8 |7 3 6 |2 4 .
+    }
+    end
+  end
+end