Test the existing behaviour of ResultSet.
user
```ruby
require "test_helper"
require "document"
require "elasticsearch/result_set"

class ResultSetTest < ShouldaUnitTestCase

  FIELDS = %w(link title description format)

  def mappings
    {
      "edition" => {
        "properties" => Hash[FIELDS.map { |f| [f, { "type" => "foo" }] }]
      }
    }
  end

  context "empty result set" do
    setup do
      @response = {
        "hits" => {
          "total" => 0,
          "hits" => []
        }
      }
    end

    should "report zero results" do
      assert_equal 0, ResultSet.new(mappings, @response).total
    end

    should "have an empty result set" do
      assert_equal 0, ResultSet.new(mappings, @response).results.size
    end
  end

  context "single result" do
    setup do
      @response = {
        "hits" => {
          "total" => 1,
          "hits" => [
            {
              "_score" => 12,
              "_source" => { "foo" => "bar" }
            }
          ]
        }
      }
    end

    should "report one result" do
      assert_equal 1, ResultSet.new(mappings, @response).total
    end

    should "pass the fields to Document.from_hash" do
      expected_hash = has_entry("foo", "bar")
      Document.expects(:from_hash).with(expected_hash, mappings).returns(:doc)

      assert_equal [:doc], ResultSet.new(mappings, @response).results
    end

    should "pass the result score to Document.from_hash" do
      expected_hash = has_entry("es_score", 12)
      Document.expects(:from_hash).with(expected_hash, mappings).returns(:doc)

      assert_equal [:doc], ResultSet.new(mappings, @response).results
    end
  end
end
```
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