.. _tutorial-scenario-outlines:

scenario outlines
=================

On our :ref:`first description file<tutorial-simple>`, `zero.feature`, all scenarios were
similar. This made us repeat most of the text again and again.

**Isn't there a better way to deal with this - when several scenarios are almost equal and only some values change?**

Yes, there is! :) You just need to use scenarios outlines.

An example is shown bellow:

.. highlight:: ruby

::

    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>
        When I compute its factorial
        Then I see the number <result>

      Examples:
        | number | result |
        | 0      | 1      |
        | 1      | 1      |
        | 2      | 2      |
        | 3      | 6      |
        | 4      | 24     |

This way, you will only need to provide the values that really change,
reducing "copy & paste" work and making your tests more clear.

.. Note::

   If you overwrite zero.feature using the example above, and goto
   step [e], you'll see your description expanding to the five
   previous scenarious:

.. image:: ./screenshot7.png

.. _Lettuce: http://lettuce.it
.. _Python: http://python.org
.. _Cucumber: http://cukes.info
.. _Ruby: http://ruby-lang.org/
.. _BDD: http://en.wikipedia.org/wiki/Behavior_Driven_Development