attributes custom matcher for minitest

gistfile1.rb

# -*- coding: utf-8 -*-
class EqualAttributesMatcher
  def initialize(attrs)
    @attrs = attrs
  end

  def matches?(model)
    @model = model
    @attrs.all? { |k,v| @model.send(k) == v }
  end

  def failure_message_for_should
    left_diff = @attrs.reject {|k,v| @model.send(k) == v}
    right_diff = left_diff.each_with_object({}) {|(k,_), hash| hash[k] = @model[k] }
    "expected #{@attrs} but diff -#{left_diff} +#{right_diff}}"
  end

  def failure_message_for_should_not
    "expected not equal #{@attrs} but equal"
  end
end

MiniTest::Unit::TestCase.register_matcher EqualAttributesMatcher, :have_equal_attributes