Add a simple helper function to find out whether we have been configured for Sauce Labs or not

lib/sauce/heroku/cli.rb

@@ -58,6 +58,12 @@ access_key: #{apikey}
       def chrome
         display 'Sauce for Heroku has not yet been configured!'
       end
+
+
+      def configured?
+        File.exists?('ondemand.yml') ||
+          File.exists?(File.expand_path('~/.sauce/ondemand.yml'))
+      end
     end
   end
 end

spec/sauce_spec.rb

@@ -2,4 +2,26 @@ require 'spec_helper'
 
 describe Heroku::Command::Sauce do
   it { should be_instance_of Heroku::Command::Sauce }
+
+  describe '#configured?' do
+    let(:exists) { false }
+
+    before :each do
+      File.stub(:exists?).with(
+          'ondemand.yml').and_return(exists)
+      File.stub(:exists?).with(
+          File.expand_path('~/.sauce/ondemand.yml')).and_return(exists)
+    end
+
+
+    context 'by default' do
+      it { subject.should_not be_configured }
+    end
+
+    context 'when configured' do
+      let(:exists) { true }
+
+      it { subject.should be_configured }
+    end
+  end
 end