Ruby ISO 8601 duration converter

convert_duration_to_seconds.rb

require 'test/unit'

# implementation
class Duration
  def in_seconds(raw_duration)
    match = raw_duration.match(/PT(?:([0-9]*)H)*(?:([0-9]*)M)*(?:([0-9.]*)S)*/)
    hours   = match[1].to_i
    minutes = match[2].to_i
    seconds = match[3].to_f
    seconds + (60 * minutes) + (60 * 60 * hours)
  end
end

# tests
class TestDuration < Test::Unit::TestCase
  def setup
    @duration = Duration.new
  end

  def test_just_seconds_with_decimal
    assert @duration.in_seconds('PT23.162S') == 23.162
  end

  def test_just_seconds_without_decimal
    assert @duration.in_seconds('PT23S') == 23
  end

  def test_minutes_and_seconds_with_decimal
    assert @duration.in_seconds('PT2M4.123S') == 124.123
  end

  def test_minutes_and_seconds_without_decimal
    assert @duration.in_seconds('PT2M4S') == 124
  end

  def test_hours_minutes_and_seconds_with_decimal
    assert @duration.in_seconds('PT1H2M4.7S') == 3724.7
  end

  def test_hours_minutes_and_seconds_without_decimal
    assert @duration.in_seconds('PT1H2M4S') == 3724
  end

  def test_hours_seconds_no_minutes
    assert @duration.in_seconds('PT1H6S') == 3606
  end

  def test_hours_minutes_no_seconds
    assert @duration.in_seconds('PT1H1M') == 3660
  end

  def test_just_hours
    assert @duration.in_seconds('PT4H') == 14_400
  end

  def test_hours_and_seconds
    assert @duration.in_seconds('PT4H1.04S') == 14_401.04
  end
end