Lettuce

Adapted from scenario outlines

Feature: Compute factorial
  In order to play with Lettuce
  As beginners
  We'll implement factorial

  Scenario Outline: Factorials [0-4]
    Given I have the number <number> and the description <description>
    When I compute its factorial
    Then I see the number <result>

  Examples:
    | number | result | description |
    | 0      | 1      | Pat         |
    | 1      | 1      | Patrick K   |
    | 2      | 2      | LLW drums   |
    | 3      | 6      | 1 2 3       |
    | 4      | 24     | Eggs Ham    |

@step('I have the number (\d+) and the description (.*)')
def have_the_number(step, number, description):
    logger.debug(description)
    world.number = int(number)

@step('I compute its factorial')
def compute_its_factorial(step):
    world.number = factorial(world.number)

@step('I see the number (\d+)')
def check_number(step, expected):
    expected = int(expected)
    assert world.number == expected, \
        "Got %d" % world.number

def factorial(number):
    number = int(number)
    if (number == 0) or (number == 1):
        return 1
    else:
        return number*factorial(number-1)