An RSpec matcher to check for intersection between two enumerables

intersect_with_matcher.rb

Spec::Matchers.define :intersect_with do |challenge_range|
  # Check to see if any elements exist in the intersection
  match do |current_range|
    [current_range.to_a & challenge_range.to_a].flatten.any?
  end

  failure_message_for_should do |current_range|
    "#{current_range.inspect} doesn't overlap with #{challenge_range.inspect}"
  end

  failure_message_for_should_not do |current_range|
    "#{current_range.inspect} overlaps with #{challenge_range.inspect}"
  end

  description do
    "intersection of an enumerable's elements"
  end
end