Prevent confusion between Huginn services and strings

- agent.service was returning an unexpected string when traversing
  all agents.
- helps with issue huginn#968 which deals with import/export

app/models/agents/weather_agent.rb

@@ -71,8 +71,16 @@ def default_options
         'expected_update_period_in_days' => '2'
       }
     end
+
+    def check
+      if key_setup?
+        create_event :payload => model(weather_provider, which_day).merge('location' => location)
+      end
+    end
 
-    def service
+    private
+
+    def weather_provider
       interpolated["service"].presence || "wunderground"
     end
 
@@ -85,8 +93,7 @@ def location
     end
 
     def validate_options
-      errors.add(:base, "service is required") unless service.present?
-      errors.add(:base, "service must be set to 'forecastio' or 'wunderground'") unless ["forecastio", "wunderground"].include?(service)
+      errors.add(:base, "service must be set to 'forecastio' or 'wunderground'") unless ["forecastio", "wunderground"].include?(weather_provider)
       errors.add(:base, "location is required") unless location.present?
       errors.add(:base, "api_key is required") unless key_setup?
       errors.add(:base, "which_day selection is required") unless which_day.present?
@@ -104,10 +111,10 @@ def forecastio
       end
     end
 
-    def model(service,which_day)
-      if service == "wunderground"
+    def model(weather_provider,which_day)
+      if weather_provider == "wunderground"
         wunderground[which_day]
-      elsif service == "forecastio"
+      elsif weather_provider == "forecastio"
         forecastio.each do |value|
           timestamp = Time.at(value.time)
           if (timestamp.to_date - Time.now.to_date).to_i == which_day
@@ -174,12 +181,5 @@ def model(service,which_day)
         end
       end
     end
-
-    def check
-      if key_setup?
-        create_event :payload => model(service, which_day).merge('location' => location)
-      end
-    end
-
   end
 end

spec/models/agents/weather_agent_spec.rb

@@ -0,0 +1,28 @@
+require 'spec_helper'
+
+describe Agents::WeatherAgent do
+  let(:agent) do
+    Agents::WeatherAgent.create(
+      name: 'weather',
+      options: { 
+        :location => 94103, 
+        :lat => 37.779329, 
+        :lng => -122.41915, 
+        :api_key => 'test' 
+      }
+    ).tap do |agent|
+      agent.user = users(:bob)  
+      agent.save!
+    end
+  end
+
+  it "creates a valid agent" do
+    expect(agent).to be_valid
+  end
+
+  describe "#service" do
+    it "doesn't have a Service object attached" do
+      expect(agent.service).to be_nil
+    end
+  end
+end