Ensure that construct returns the correct zone when the score is right on a benchmark

spec/models/construct_spec.rb

@@ -15,4 +15,31 @@ describe Construct, type: :model do
     expect(construct.approval_zone).to eq Construct::Zone.new(3.5, 4.71, :approval)
     expect(construct.ideal_zone).to eq Construct::Zone.new(4.71, 5.0, :ideal)
   end
+
+  describe '#zone_for_score' do
+    let(:construct) {
+      Construct.new watch_low_benchmark: 1.5, growth_low_benchmark: 2.5, approval_low_benchmark: 3.5, ideal_low_benchmark: 4.5
+    }
+
+    context 'when the score is 1.0' do
+      it 'returns the warning zone' do
+        expect(construct.zone_for_score(1.0)).to eq construct.warning_zone
+      end
+    end
+
+    context 'when the score is 5.0' do
+      it 'returns the ideal zone' do
+        expect(construct.zone_for_score(5.0)).to eq construct.ideal_zone
+      end
+    end
+
+    context 'when the score is right on the benchmark' do
+      it 'returns the higher zone' do
+        expect(construct.zone_for_score(1.5)).to eq construct.watch_zone
+        expect(construct.zone_for_score(2.5)).to eq construct.growth_zone
+        expect(construct.zone_for_score(3.5)).to eq construct.approval_zone
+        expect(construct.zone_for_score(4.5)).to eq construct.ideal_zone
+      end
+    end
+  end
 end