冗余和重复的产生，考虑如下场景

Feature: movies should appear in alphabetical order, not added order

Scenario: view movie list after adding 2 movies (imperative and non-DRY)

  Given I am on the RottenPotatoes home page
  When I follow "Add new movie"
  Then I should be on the Create New Movie page
  When I fill in "Title" with "Zorro"
  And I select "PG" from "Rating"
  And I press "Save Changes"
  Then I should be on the RottenPotatoes home page
  When I follow "Add new movie"
  Then I should be on the Create New Movie page
  When I fill in "Title" with "Apocalypse Now"
  And I select "R" from "Rating"
  And I press "Save Changes"
  Then I should be on the RottenPotatoes home page
  Then I should see "Apocalypse Now" before "Zorro" on the RottenPotatoes home page sorted by title

这个写法无疑又太多的重复，对比如下描述

Feature: movies should appear in alphabetical order, not added order

Scenario: view movie list after adding movie (declarative and DRY)

  Given I have added "Zorro" with rating "PG-13"
  And   I have added "Apocalypse Now" with rating "R"
  Then  I should see "Apocalypse Now" before "Zorro" on the RottenPotatoes home page sorted by title

这种描述就很简洁。所以只需添加features/step_definitions/declarative_steps.rb

Given /I have added "(.*)" with rating "(.*)"/ do |title, rating|
  steps %Q{
    Given I am on the Create New Movie page
    When  I fill in "Title" with "#{title}"
    And   I select "#{rating}" from "Rating"
    And   I press "Save Changes"
  }
end

Then /I should see "(.*)" before "(.*)" on (.*)/ do |string1, string2, path|
  step "I am on #{path}"
  regexp = /#{string1}.*#{string2}/m #  /m means match across newlines
  page.body.should =~ regexp
end