[BUU] Handle corrupt data and troubleshooting

app/services/weights_and_measures.rb

@@ -15,17 +15,19 @@ def scale_for_unit_value
 
   def system
     return "custom" unless scales = scales_for_variant_unit(ignore_available_units: true)
-    return "custom" unless product_scale = @variant.product.variant_unit_scale
 
-    scales[product_scale.to_f]['system']
+    product_scale = @variant.product.variant_unit_scale&.to_f
+    return "custom" unless product_scale.present? && product_scale.positive?
+
+    scales[product_scale]['system']
   end
 
   # @returns enumerable with label and value for select
   def self.variant_unit_options
     available_units_sorted.flat_map do |measurement, measurement_info|
       measurement_info.filter_map do |scale, unit_info|
         scale_clean =
-          ActiveSupport::NumberHelper.number_to_rounded(scale, precision: nil,
+          ActiveSupport::NumberHelper.number_to_rounded(scale, precision: nil, significant: false,
                                                                strip_insignificant_zeros: true)
         [
           "#{I18n.t(measurement)} (#{unit_info['name']})", # Label (eg "Weight (g)")

spec/services/weights_and_measures_spec.rb

@@ -58,6 +58,45 @@
         expect(subject.system).to eq("custom")
       end
     end
+
+    # In the event of corrupt data, we don't want an exception
+    context "corrupt data" do
+      it "when unit is invalid, scale is valid" do
+        allow(product).to receive(:variant_unit) { "blah" }
+        allow(product).to receive(:variant_unit_scale) { 1.0 }
+        expect(subject.system).to eq("custom")
+      end
+
+      it "when unit is invalid, scale is nil" do
+        allow(product).to receive(:variant_unit) { "blah" }
+        allow(product).to receive(:variant_unit_scale) { nil }
+        expect(subject.system).to eq("custom")
+      end
+
+      it "when unit is nil, scale is valid" do
+        allow(product).to receive(:variant_unit) { nil }
+        allow(product).to receive(:variant_unit_scale) { 1.0 }
+        expect(subject.system).to eq("custom")
+      end
+
+      it "when unit is nil, scale is nil" do
+        allow(product).to receive(:variant_unit) { nil }
+        allow(product).to receive(:variant_unit_scale) { nil }
+        expect(subject.system).to eq("custom")
+      end
+
+      it "when unit is valid, but scale is nil" do
+        allow(product).to receive(:variant_unit) { "weight" }
+        allow(product).to receive(:variant_unit_scale) { nil }
+        expect(subject.system).to eq("custom")
+      end
+
+      it "when unit is valid, but scale is 0" do
+        allow(product).to receive(:variant_unit) { "weight" }
+        allow(product).to receive(:variant_unit_scale) { 0.0 }
+        expect(subject.system).to eq("custom")
+      end
+    end
   end
 
   describe "#variant_unit_options" do