custom_matchers.rb

module CustomMatchers

  class HaveActiveRecordTimestamps
    def description
      "have the active record timestamp columns created_at and updated_at"
    end

    def initialize()
    end

    def failure_message
      "#{@object.class_name} is missing the active record timestamp columns created_at and updated_at"
    end

    def matches?(object)
      @object = object
      @object.respond_to?(:created_at) && @object.respond_to?(:updated_at)
    end

    def negative_failure_message
      "#{@object.class_name} is has the active record timestamp columns created_at and updated_at"
    end
  end

  def have_active_record_timestamps
    HaveActiveRecordTimestamps.new
  end

  class ValidateLengthOf

    def description
      "only allow a #{@restriction} of #{@value} characters for #{@attribute}"
    end

    def initialize(attribute, restriction, value)
      @attribute   = attribute
      @restriction = restriction
      @value       = value
    end

    def failure_message
      "The restriction of a #{@restriction} of #{@value} characters is not being correctly enforced on #{@attribute}"
    end

    def matches?(object)
      @object = object
      @object.send("#{@attribute}=", '*' * @value)
      @object.valid?
      edge_value_excepted = @object.errors_on(@attribute).blank?
      bumpped_value = case @restriction
        when :minimum then @value -1
        else @value + 1
      end
      @object.send("#{@attribute}=", '*' * bumpped_value)
      @object.valid?
      [email protected]_on(@attribute).blank? && edge_value_excepted
    end

    def negative_failure_message
      "It does not really make sense to negate this test! ValidatesLengthOf"
    end

  end

  def validate_length_of(attribute, restriction, value)
    ValidateLengthOf.new(attribute, restriction, value)
  end

end