Diff.rb

require 'optparse'

class Diff
  def initialize(new, old, delimiter = ' ')
    @new = new
    @old = old
    @delimiter = delimiter
  end

  def file_each_line(file)
    raise "No block" unless block_given?
    File.open(file) do |f|
      f.each_line do |line|
        yield line
      end
    end
  end

  def init
    @new_hash = Hash.new
    file_each_line(@new) do |line|
      checksum, path = line.split(@delimiter)
      @new_hash[path] = checksum
    end
  end

  def checksum
    init
    result = []
    file_each_line(@old) do |line|
      checksum, path = line.split(@delimiter)
      result << path if @new_hash.has_key?(path) && @new_hash[path] != checksum
    end
    result
  end

  def exists_only_in_old
    init
    result = []
    file_each_line(@old) do |line|
      checksum, path = line.split(@delimiter)
      result << path unless @new_hash.has_key?(path)
    end
    result
  end

  def exists_only_in_new
    init
    file_each_line(@old) do |line|
      checksum, path = line.split(@delimiter)
      @new_hash.delete(path)
    end
    @new_hash.keys
  end
end

if __FILE__ == $0
  args = {}
  OptionParser.new do |parser|
    parser.on('-m', '--method METHOD_NAME') {|v| args[:method] = v }
    parser.parse!(ARGV)
  end
  args[:method] = 'checksum' unless args[:method]

  diff = Diff.new($*[0], $*[1])
  raise 'invalid argument' unless diff.respond_to?(args[:method])
  puts diff.send(args[:method])
end

Diff_spec.rb

require './Diff.rb'

describe Diff do
  before :each do
    @diff = Diff.new('filepath_dummy1', 'filepath_dummy2');
  end

  describe '#initialize' do
    context 'when passed filepath' do
      it 'set it to property' do
        @diff.instance_eval { @new }.should == 'filepath_dummy1'
        @diff.instance_eval { @old }.should == 'filepath_dummy2'
      end
    end
    context 'when passed nothing to delimiter' do
      it 'set single space to delimiter' do
        @diff.instance_eval { @delimiter }.should == ' '
      end
    end
    context 'when passed something to delimiter' do
      it 'set it to delimiter' do
        delimiter = '---'
        delimiter_set = Diff.new('dummy1.txt', 'dummy2.txt', delimiter)
        delimiter_set.instance_eval { @delimiter }.should == delimiter
      end
    end
  end

  describe '#file_each_line' do
    context 'when block is not given' do
      it 'should raise RuntimeError' do
        lambda{ @diff.file_each_line('dummy.txt') }.should raise_error
      end
    end
  end

  describe 'check method' do
    before :each do
      @dummy1 =<<'EOS'
7e0214a120fecc15ef524f15187a70b9 ./websocket/server/server.rb
4786f7b4e011d1e243347b91e5cb7f1d ./websocket/js/ws.js
d3fd67f82c6ab0b7ac6a359375f0dff0 ./websocket/index3.html
d3fd67f82c6ab0b7ac6a359375f0dff0 ./websocket/index2.html
c0603d5a956c75407a9110ffd08e30d7 ./websocket/index.html
605632f7874dedb4de036350c187b933 ./using_test.rb
EOS
      @dummy2 =<<'EOS'
7e0214a120fecc15ef524f15187a70bf ./websocket/server/server.rb
4786f7b4e011d1e243347b91e5cb7f1f ./websocket/js/ws.js
d3fd67f82c6ab0b7ac6a359375f0dff0 ./websocket/index3.html
c0603d5a956c75407a9110ffd08e30df ./websocket/index.html
605632f7874dedb4de036350c187b933 ./using_test.rb
4c925a413d88e74bcb7f26ab447ffeeb ./using.rb
EOS
      dummy1 = @dummy1
      dummy2 = @dummy2
      (class << @diff; self; end;).class_eval do
        define_method(:file_each_line) do |filepath, &block|
          target = filepath == 'filepath_dummy1' ? dummy1 : dummy2
          target.split("\n").each do |line|
            block.call(line)
          end
        end
      end
    end

    describe '#init' do
      it 'should set dummy1 to @new_hash' do
        @diff.init
        expect = Hash.new
        @dummy1.split("\n").each do |line|
          value, key = line.split(' ')
          expect[key] = value
        end
        @diff.instance_eval { @new_hash }.should == expect
      end
    end

    describe '#checksum' do
      it 'should return array' do
        @diff.checksum.should be_kind_of(Array)
      end
      it 'should return the file path the checksum are different' do
        @diff.checksum.should == %w{./websocket/server/server.rb ./websocket/js/ws.js ./websocket/index.html}
      end
    end

    describe '#exists_only_in_old' do
      it 'should return array' do
        @diff.exists_only_in_old.should be_kind_of(Array)
      end
      it 'should return the file path the exists only in old(dummy2)' do
        @diff.exists_only_in_old.should == %w{./using.rb}
      end
    end

    describe '#exists_only_in_new' do
      it 'should return array' do
        @diff.exists_only_in_new.should be_kind_of(Array)
      end
      it 'should return the file path the exists only in new(dummy1)' do
        @diff.exists_only_in_new.should == %w{./websocket/index2.html}
      end
    end
  end
end