Return nil when Google provides no city.

Fixes #56

lib/geocoder/results/google.rb

@@ -20,6 +20,7 @@ module Geocoder::Result
           return entity['long_name']
         end
       end
+      return nil # no appropriate components found
     end
 
     def state

test/fixtures/google_no_city_data.json

+{
+  "status": "OK",
+  "results": [ {
+    "types": [ "postal_code" ],
+    "formatted_address": "55100, Turkey",
+    "address_components": [{
+      "long_name": "55100",
+      "short_name": "55100",
+      "types": ["postal_code"]
+     },
+     {
+      "long_name": "Turkey",
+      "short_name": "TR",
+      "types": ["country", "political"]
+     }],
+     "geometry": {
+        "location": {
+          "lat": 41.3112221,
+          "lng": 36.3322118
+        },
+        "location_type": "APPROXIMATE",
+        "viewport": {
+          "southwest": {
+              "lat": 41.2933411,
+              "lng": 36.3066331
+          },
+          "northeast": {
+              "lat": 41.3291031,
+              "lng": 36.3577906
+          }
+        },
+        "bounds": {
+          "southwest": {
+              "lat": 41.2933411,
+              "lng": 36.3066331
+          },
+          "northeast": {
+              "lat": 41.3291031,
+              "lng": 36.3577906
+          }
+        }
+      }
+  } ]
+}
\ No newline at end of file

test/geocoder_test.rb

@@ -370,6 +370,10 @@ class GeocoderTest < Test::Unit::TestCase
     assert_equal "Haram", result.city
   end
 
+  def test_google_city_results_returns_nil_if_no_matching_component_types
+    result = Geocoder.search("no city data").first
+    assert_equal nil, result.city
+  end
 
   # --- Yahoo ---
 

test/test_helper.rb

@@ -63,9 +63,10 @@ module Geocoder
       def fetch_raw_data(query, reverse = false)
         raise TimeoutError if query == "timeout"
         file = case query
-          when "no results";  :no_results
-          when "no locality"; :no_locality
-          else                :madison_square_garden
+          when "no results";   :no_results
+          when "no locality";  :no_locality
+          when "no city data"; :no_city_data
+          else                 :madison_square_garden
         end
         read_fixture "google_#{file}.json"
       end