RSpec matcher

allow.rb

RSpec::Matchers.define :allow do |*values|
  match do |record|
    values.collect {|value|
      record.send("#{@attribute}=", value)
      record.valid?
      record.errors[@attribute].empty?
    }.all?
  end

  chain :as do |attribute|
    @attribute = attribute
  end

  failure_message_for_should do |record|
    "expected #{record.inspect} to allow each of #{values.inspect} as #{@attribute.inspect} value"
  end

  failure_message_for_should_not do |record|
    "expected #{record.inspect} to reject each of #{values.inspect} as #{@attribute.inspect} value"
  end

  description do
    "allow #{values.inspect} values for #{@attribute.inspect}"
  end
end