temperature.rb

class Temperature
  def ftoc(f)
    (f-32) * (5.0/9.0)
  end
  
  def ctof(c)
    c * (9.0/5.0) + 32
  end
end

temperature_spec.rb

require "#{File.dirname(__FILE__)}/temperature"

describe Temperature do
  
  before do
    @temperature = Temperature.new
  end

  describe "#ftoc" do
    
    it "converts freezing temperature" do
      @temperature.ftoc(32).should == 0
    end
    
    it "converts boiling temperature" do
      @temperature.ftoc(212).should == 100
    end
    
    it "converts body temperature" do
      @temperature.ftoc(98.6).should == 37
    end
    
    it "converts arbitrary temperature" do
      @temperature.ftoc(68).should == 20
    end
    
  end

  describe "#ctof" do
    
    it "converts freezing temperature" do
      @temperature.ctof(0).should == 32
    end
    
    it "converts boiling temperature" do
      @temperature.ctof(100).should == 212
    end

    it "converts arbitrary temperature" do
      @temperature.ctof(20).should == 68
    end

    it "converts body temperature" do
       t = @temperature.ctof(37)
       (t*10).round.should == 986 # see http://www.ruby-forum.com/topic/169330#742994
    end
    
    
  end

end