Raise NotFound when we can't find a set

lib/brickset/models/legoset.rb

@@ -25,4 +25,6 @@ def url
       "https://brickset.com/sets/#{@legoset_id}-1"
     end
   end
+
+  class Legoset::NotFound < StandardError; end
 end

lib/brickset/services/get_legoset.rb

@@ -19,10 +19,13 @@ def legoset
       end
 
       def parse_details(html)
-        # TODO: refactor / cleanup
         details = { }
         eol = 0
-        html.css('section.featurebox dl').css('dt,dd').to_a.each_slice(2) do |dt, dd|
+
+        featurebox = html.css('section.featurebox dl')
+        raise Brickset::Legoset::NotFound unless featurebox.any?
+
+        featurebox.css('dt,dd').to_a.each_slice(2) do |dt, dd|
           case dt.text.strip
           when 'Name'
             details[:name] = dd.text

spec/brickset/services/get_legoset_spec.rb

@@ -17,5 +17,13 @@
         expect(subject.send(attr)).to be_present
       end
     end
+
+    context 'for an inexistent set', vcr: { cassette_name: 'not_found' } do
+      let(:legoset_id) { '123456' }
+
+      it 'raises a not found exception' do
+        expect { subject }.to raise_error(Brickset::Legoset::NotFound)
+      end
+    end
   end
 end