Mock geocoding in Rspec, with _specifics for `Google Geocoding API`

mock_geocoder.rb

# In spec_helper:
# RSpec.configure do |config|
#   ...
#   config.include(MockGeocoder)
# end
#
# In your tests:
# it 'mock geocoding' do
#   # You may pass additional params to override defaults
#   # (i.e. :coordinates => [10, 20])
#   # NB: the results from `#data` won't be changed though (not implemented)
#   mock_geocoding!
#   address = Factory(:address)
#   address.lat.should eq(1)
#   address.lng.should eq(2)
# end
#

require 'geocoder/results/base'

module MockGeocoder
  def self.included(base)
    base.before :each do
      allow(::Geocoder).to receive(:search).and_raise(
        RuntimeError.new('Use "mock_geocoding!" method in your tests.')
      )
    end
  end

  def mock_geocoding!(options = {})
    # Sample data attribute which contains the complete response of Google API
    # > "...call the #data method of any Geocoder::Result object to get the full parsed response."
    # @link https://github.com/alexreisner/geocoder#advanced-geocoding
    mock_data = {
      "address_components" => [
        { "long_name" => "Marseille", "short_name" => "Marseille", "types" => %w[locality political] },
        { "long_name" => "Bouches-du-Rhône", "short_name" => "Bouches-du-Rhône", "types" => %w[administrative_area_level_2 political] },
        { "long_name" => "Provence-Alpes-Côte d'Azur", "short_name" => "Provence-Alpes-Côte d'Azur", "types" => %w[administrative_area_level_1 political] },
        { "long_name" => "France", "short_name" => "FR", "types" => %w[country political] }
      ],
      "formatted_address" => "Marseille, France",
      "geometry" => {
        "bounds" => {
          "northeast" => { "lat" => 43.3911601, "lng" => 5.5323519 },
          "southwest" => { "lat" => 43.169621, "lng" => 5.228641 }
        },
        "location" => { "lat" => 43.296482, "lng" => 5.36978 },
        "location_type" => "APPROXIMATE",
        "viewport" => { "northeast" => { "lat" => 43.3911601, "lng" => 5.5323519 }, "southwest" => { "lat" => 43.169621, "lng" => 5.228641 } }
      },
      "place_id" => "ChIJM1PaREO_yRIRIAKX_aUZCAQ",
      "types" => %w[locality political]
    }

    options.reverse_merge!(address: "Marseille, France",
                           coordinates: [43.296482, 5.36978],
                           state: "Provence-Alpes-Côte d'Azur",
                           state_code: "Provence-Alpes-Côte d'Azur",
                           country: "France",
                           country_code: "FR",
                           'address_components': {
                             'types':  %w[locality political],
                             'long_name': "Marseille",
                             'short_name': "Marseille"
                           })

    MockResult.new(mock_data).tap do |result|
      options.each do |prop, val|
        allow(result).to receive(prop).and_return(val)
      end
      allow(Geocoder).to receive(:search).and_return([result])
    end
  end

  class MockResult < ::Geocoder::Result::Google
    def initialize(data = [])
      super(data)
    end
  end
end

RSpec.configure do |config|
  config.include MockGeocoder
end