Rspec matchers combinators

matchers_combinators.rb

# Matcher to verify that all items match something else
RSpec::Matchers.define :all_ do |item_matcher|

  match do |actual_items|
    actual_items.all? { |item| item_matcher.matches?(item)}
  end

  description do
    "#{item_matcher.description} to be true for all the items"
  end

end

# Matcher to verify that at least one item matches something else
RSpec::Matchers.define :have_one_that do |item_matcher|

  match do |actual_items|
    actual_items.any? { |item| item_matcher.matches?(item)}
  end

  description do
    "#{item_matcher.description} to be true for at least one item"
  end

end

# Matcher to verify that an item matches all matchers in a list
RSpec::Matchers.define :and_ do |*matchers|

  match do |actual|
    matchers.all? {|matcher| matcher.matches?(actual) }
  end

  description do
    (matchers.map &:description).join(" and ")
  end

end