Refactor option_value_value_unit_scaled for correct unit value scaling and update sales tax report spec for clarity

Author: Neal Chambers

app/services/variant_units/option_value_namer.rb

@@ -58,7 +58,7 @@ def option_value_value_unit
     def option_value_value_unit_scaled
       unit_scale, unit_name = scale_for_unit_value
 
-      value = (@nameable.unit_value / unit_scale).to_d.round(2)
+      value = (@nameable.unit_value.to_d / unit_scale).round(2)
 
       [value, unit_name]
     end

spec/lib/reports/sales_tax_totals_by_order_spec.rb

@@ -145,7 +145,8 @@
         total = report.total_excl_tax(query_row)
 
         # discounted order total - discounted order tax
-        expect(total).to eq((BigDecimal('113.3') - 10) - (BigDecimal('3.3') - BigDecimal('0.29')))
+        # (113.3 - 10) - (3.3 - 0.29)
+        expect(total).to eq 100.29
       end
     end
   end