document_analyzer.rb

class DocumentAnalyzer
  SPLIT_STRATEGY = lambda { |doc| doc.split(' ').size }

  def initialize(document)
    @document = document
  end

  def word_count(counting_strategy = SPLIT_STRATEGY)
    counting_strategy.call(@document)
  end

  def phrase_count(phrase)
    @document.scan(phrase).count
  end
end

document_analyzer_spec.rb

$LOAD_PATH.unshift(File.dirname(__FILE__))
$LOAD_PATH.unshift(File.join(File.dirname(__FILE__), '..', 'lib'))
require 'rubygems'
require 'spec'
require 'spec/autorun'
require 'document_analyzer'

begin
  require 'ruby-debug'
  Debugger.start
  Debugger.settings[:autoeval] = true if Debugger.respond_to?(:settings)
rescue LoadError
  # ruby-debug wasn't available so neither can the debugging be
end


Spec::Runner.configure do |config|
end

describe DocumentAnalyzer do
  describe 'a new instance' do
    subject { DocumentAnalyzer.new("this is a sentence with some words") }

    it 'returns the word count from #word_count' do
      subject.word_count.should == 7
    end
  end

  it 'counts words for a document with double spaces and tabs correctly' do
    da = DocumentAnalyzer.new("these\t   is     some words")
    da.word_count.should == 4
  end

  it 'counts phrases' do
    da = DocumentAnalyzer.new("this is a sentence with some words. this is a sentence with some words")
    da.phrase_count('some words').should == 2
  end
end