         diff = @choroplethMap.calculateDifference(@oldSnippetModel)
         expect(diff[3].properties[1]).to.eql
           label: 'color scheme'
+          key: 'colorScheme'
           difference: undefined
           info: '(YlGn)'
 

        diff = @choroplethMap.calculateDifference(@oldSnippetModel)
        expect(diff[0].properties[1]).to.eql(
          label: 'projection'
          difference:
            type: 'change'
            previous: 'mercator'

        diff = @choroplethMap.calculateDifference(@oldSnippetModel)
        expect(diff[3].properties[2]).to.eql
          label: 'quantize steps'
          key: 'quantizeSteps'
          difference: undefined
          info: '(3)'

