Take tax_category from Line Items and Fix validation: rounding for su…

…bcent amounts (#14)

* fix tax rounding for sub-cent amounts

* adjust spec so that we still test quantity working

* use tax_category per tax rate

lib/secretariat/invoice.rb

@@ -54,17 +54,17 @@ def tax_reason_text
       tax_reason || TAX_EXEMPTION_REASONS[tax_category]
     end
 
-    def tax_category_code(version: 2)
+    def tax_category_code(tax, version: 2)
       if version == 1
-        return TAX_CATEGORY_CODES_1[tax_category] || 'S'
+        return TAX_CATEGORY_CODES_1[tax.tax_category || tax_category] || 'S'
       end
-      TAX_CATEGORY_CODES[tax_category] || 'S'
+      TAX_CATEGORY_CODES[tax.tax_category || tax_category] || 'S'
     end
 
     def taxes
       taxes = {}
       line_items.each do |line_item|
-        taxes[line_item.tax_percent] = Tax.new(tax_percent: BigDecimal(line_item.tax_percent)) if taxes[line_item.tax_percent].nil?
+        taxes[line_item.tax_percent] = Tax.new(tax_percent: BigDecimal(line_item.tax_percent), tax_category: line_item.tax_category) if taxes[line_item.tax_percent].nil?
         taxes[line_item.tax_percent].tax_amount += BigDecimal(line_item.tax_amount)
         taxes[line_item.tax_percent].base_amount += BigDecimal(line_item.net_amount) * line_item.quantity
       end
@@ -91,7 +91,7 @@ def valid?
       end
       taxes.each do |tax|
         calc_tax = tax.base_amount * BigDecimal(tax.tax_percent) / BigDecimal(100)
-        calc_tax = calc_tax.round(2, :down)
+        calc_tax = calc_tax.round(2)
         if tax.tax_amount != calc_tax
           @errors << "Tax amount and calculated tax amount deviate for rate #{tax.tax_percent}: #{tax.tax_amount} / #{calc_tax}"
           return false
@@ -230,7 +230,7 @@ def to_xml(version: 1, validate: true)
                     xml['ram'].ExemptionReason tax_reason_text
                   end
                   Helpers.currency_element(xml, 'ram', 'BasisAmount', tax.base_amount, currency_code, add_currency: version == 1)
-                  xml['ram'].CategoryCode tax_category_code(version: version)
+                  xml['ram'].CategoryCode tax_category_code(tax, version: version)
 
                   percent = by_version(version, 'ApplicablePercent', 'RateApplicablePercent')
                   xml['ram'].send(percent, Helpers.format(tax.tax_percent))

lib/secretariat/line_item.rb

@@ -65,6 +65,7 @@ def valid?
       end
 
       calculated_tax = charge_price * BigDecimal(tax_percent) / BigDecimal(100)
+      calculated_tax = calculated_tax.round(2)
       if calculated_tax != tax
         @errors << "Tax and calculated tax deviate: #{tax} / #{calculated_tax}"
         return false

lib/secretariat/tax.rb

@@ -20,6 +20,7 @@ module Secretariat
   Tax = Struct.new('Tax',
     :tax_percent,
     :tax_amount,
+    :tax_category,
     :base_amount,
     keyword_init: true
   ) do

test/invoice_test.rb

@@ -130,27 +130,40 @@ def make_de_invoice_with_multiple_tax_rates
       )
       line_item = LineItem.new(
         name: 'Depfu Starter Plan',
-        quantity: 1,
+        quantity: 2,
         unit: :PIECE,
         gross_amount: '23.80',
         net_amount: '20',
-        charge_amount: '20',
+        charge_amount: '40',
         tax_category: :STANDARDRATE,
         tax_percent: '19',
-        tax_amount: "3.80",
+        tax_amount: "7.60",
         origin_country_code: 'DE',
         currency_code: 'EUR'
       )
       line_item2 = LineItem.new(
         name: 'Cup of Coffee',
-        quantity: 2,
+        quantity: 1,
         unit: :PIECE,
-        gross_amount: '2.14',
-        net_amount: '2',
-        charge_amount: '4',
+        gross_amount: '2.68',
+        net_amount: '2.50',
+        charge_amount: '2.50',
         tax_category: :STANDARDRATE,
         tax_percent: '7',
-        tax_amount: "0.28",
+        tax_amount: "0.18",
+        origin_country_code: 'DE',
+        currency_code: 'EUR'
+      )
+      line_item3 = LineItem.new(
+        name: 'Returnable Deposit',
+        quantity: 1,
+        unit: :PIECE,
+        gross_amount: '5',
+        net_amount: '5',
+        charge_amount: '5',
+        tax_category: :ZEROTAXPRODUCTS,
+        tax_percent: '0',
+        tax_amount: "0",
         origin_country_code: 'DE',
         currency_code: 'EUR'
       )
@@ -162,18 +175,18 @@ def make_de_invoice_with_multiple_tax_rates
         seller: seller,
         buyer: buyer,
         buyer_reference: "112233",
-        line_items: [line_item, line_item2],
+        line_items: [line_item, line_item2, line_item3],
         currency_code: 'USD',
         payment_type: :CREDITCARD,
         payment_text: 'Kreditkarte',
         payment_iban: 'DE02120300000000202051',
         payment_terms_text: "Zahlbar innerhalb von 14 Tagen ohne Abzug",
         tax_category: :STANDARDRATE,
-        tax_amount: '4.08',
-        basis_amount: '24',
-        grand_total_amount: '28.08',
+        tax_amount: '7.78',
+        basis_amount: '47.50',
+        grand_total_amount: '55.28',
         due_amount: 0,
-        paid_amount: '28.08',
+        paid_amount: '55.28',
         payment_due_date: Date.today + 14
       )
     end
@@ -296,7 +309,7 @@ def test_de_multiple_taxes_invoice_v2
       assert_equal [], errors
     end
 
-    def test_de_multiple_taxes_invoice_against_schematron
+    def test_de_multiple_taxes_invoice_against_schematron_1
       xml = make_de_invoice_with_multiple_tax_rates.to_xml(version: 1)
       v = Validator.new(xml, version: 1)
       errors = v.validate_against_schematron
@@ -308,5 +321,17 @@ def test_de_multiple_taxes_invoice_against_schematron
       end
       assert_equal [], errors
     end
+    def test_de_multiple_taxes_invoice_against_schematron_2
+      xml = make_de_invoice_with_multiple_tax_rates.to_xml(version: 2)
+      v = Validator.new(xml, version: 2)
+      errors = v.validate_against_schematron
+      if !errors.empty?
+        puts xml
+        errors.each do |error|
+          puts "#{error[:line]}: #{error[:message]}"
+        end
+      end
+      assert_equal [], errors
+    end
   end
 end