minitest-matchers for controller/functional specs

response_matchers.rb

# Simple minitest matchers which will make your controller/functional specs less pain in the ass.
# 
# ==== Dependencies
#
# gem 'minitest'
# gem 'minitest-matchers'
#
# ==== Matchers
#
# +must_have_status+ and its opposite +wont_have_status+ take both one argument which must be one of the following:
# * <tt>:success</tt>
# * <tt>:missing</tt>
# * <tt>:redirect</tt>
# * <tt>:error</tt>
# 
# See https://github.com/rails/rails/blob/master/actionpack/lib/action_dispatch/testing/assertions/response.rb#L6
# for more info.
#
# And if you are as lazy as I am you will definitely prefer their shortcuts:
# 
# * +must_succeed+ is the same as +must_have_status(:success)+
# * +must_miss+ is the same as +must_have_status(:missing)+
# * +must_redirect+ is the same as +must_have_status(:redirect)+
# * +must_fail+ is the same as +must_have_status(:error)+
#
# And of course the shortcuts of their opposites too:
# +wont_succeed+, +wont_miss+, +wont_redirect+, +wont_fail+
#
module ResponseMatchers
  module HaveStatus
    TYPES = {
      success:  :succeed,
      missing:  :miss,
      redirect: :redirect,
      error:    :fail
    }

    class Matcher
      attr_accessor :status

      def initialize(status)
        self.status = status
      end

      def matches?(response)
        response.send("#{status}?")
      end

      def failure_message
        "Expected response to #{HaveStatus::TYPES[status]}"
      end

      def negative_failure_message
        "Expected response not to #{HaveStatus::TYPES[status]}"
      end
    end

    def have_status(status)
      Matcher.new(status)
    end
    MiniTest::Unit::TestCase.register_matcher(:have_status, :have_status)

    TYPES.each do |status, method|
      define_method(method) do
        have_status(status)
      end
      
      MiniTest::Unit::TestCase.register_matcher(method, method)
    end
  end
end

class MiniTest::Spec
  include ::ResponseMatchers::HaveStatus
end