app_helper.rb

module ApplicationHelper

  class Formatter 
    def self.format_pace(seconds)
      hours = seconds/3600.to_i
      minutes = (seconds/60 - hours *  60).to_i
      seconds_remaining = (seconds - (minutes * 60 + hours * 3600))
      if hours >= 1
        "%01d:%02d:%02d" % [hours, minutes, seconds_remaining]
      elsif minutes <= 9
        "%01d:%02d" % [minutes, seconds_remaining]
      else
        "%02d:%02d" % [minutes, seconds_remaining]
      end
    end

    def self.format_date(run)
      run.workout_datetime.to_time.strftime("%a, %m/%d/%y")
    end

    def self.format_distance(run)
      run.miles.round(2)
    end

    def self.format_run_time(seconds)
      hours = seconds/3600.to_i
      minutes = (seconds/60 - hours *  60).to_i
      seconds_remaining = (seconds - (minutes * 60 + hours * 3600))
      if hours >= 1
        "%01d:%02d:%02d" % [hours, minutes, seconds_remaining]
      elsif minutes <= 9
        "%01d:%02d" % [minutes, seconds_remaining]
      else
        "%02d:%02d" % [minutes, seconds_remaining]
      end
    end

  end

end

app_helper_spec.rb

require "spec_helper"

describe "Formatter" do
  it "formats for seconds that are more than 1 hour" do
    seconds = 4500
    formatter = ApplicationHelper::Formatter.format_pace(seconds)
    expect("1:15:00").to eq(formatter)
  end
 
  it "formats for seconds that are less than 1 hour" do
    seconds = 1500
    formatter = ApplicationHelper::Formatter.format_pace(seconds)
    expect("25:00").to eq(formatter)
  end

  it "formats for seconds that are less than 1 minute" do
    seconds = 54
    formatter = ApplicationHelper::Formatter.format_pace(seconds)
    expect("00:54").to eq(formatter)
  end

  it "can accept seconds that are integers or floats" do
    seconds = 1159.2
    formatter = ApplicationHelper::Formatter.format_pace(seconds)
    expect("19:32")
  end
end