word_count.rb

class WordCount
  def initialize(sentence)
    @sentence = sentence
  end

  def frequency
    word_counter = Hash.new(0)
    @sentence.split(' ').each do |word|
      word_counter[word.downcase] += 1
    end
    word_counter
  end
end

word_count_rspec.rb

require_relative "word_count"
require "rspec"

describe WordCount do
  require 'pry'
  it "count the frequency of each word" do
    expect(WordCount.new('Toy boat toy boat toy boat').frequency).to eql( { 'toy' => 3, 'boat' => 3 } )
  end

  it 'ignores non word or number characteristics'
end