Rspec Custom Matcher require_presence_of

require_presence_of.rb

# Matcher place into spec/support/require_presence_of.rb

RSpec::Matchers.define :require_presence_of do |attr|
  match do |model|
    model.send("#{attr}=", nil)
    !model.valid? && model.errors.has_key?(attr)
  end
end

# Sample of use

require 'spec_helper'

describe MyModel do
  let(:my_model) { Factory.build(:my_model) }
  subject { my_model }

  it "should_not accept nil price" do
    should require_presence_of(:price)
  end
end