Adyen: Update split refund method

CHANGELOG

@@ -20,6 +20,7 @@
 * Naranja: Update valid number check to include luhn10 [DustinHaefele] #5217
 * Cybersource: Add apple_pay with discover. [DustinHaefele] #5213
 * MercadoPago: Add idempotency key field [yunnydang] #5229
+* Adyen: Update split refund method [yunnydang] #5218
 
 == Version 1.137.0 (August 2, 2024)
 * Unlock dependency on `rexml` to allow fixing a CVE (#5181).

lib/active_merchant/billing/gateways/adyen.rb

@@ -435,16 +435,17 @@ def add_splits(post, options)
 
         splits = []
         split_data.each do |split|
-          amount = {
-            value: split['amount']['value']
-          }
-          amount[:currency] = split['amount']['currency'] if split['amount']['currency']
+          if split['amount']
+            amount = {}
+            amount[:value] = split['amount']['value'] if split['amount']['value']
+            amount[:currency] = split['amount']['currency'] if split['amount']['currency']
+          end
 
           split_hash = {
-            amount: amount,
             type: split['type'],
             reference: split['reference']
           }
+          split_hash[:amount] = amount unless amount.nil?
           split_hash['account'] = split['account'] if split['account']
           splits.push(split_hash)
         end

test/unit/gateways/adyen_test.rb

@@ -542,6 +542,24 @@ def test_splits_sent
     end.respond_with(successful_authorize_response)
   end
 
+  def test_splits_sent_without_amount
+    split_data = [{
+      'type' => 'MarketPlace',
+      'account' => '163298747',
+      'reference' => 'QXhlbFN0b2x0ZW5iZXJnCg'
+    }, {
+      'type' => 'Commission',
+      'reference' => 'THVjYXNCbGVkc29lCg'
+    }]
+
+    options = @options.merge({ splits: split_data })
+    stub_comms do
+      @gateway.authorize(@amount, @credit_card, options)
+    end.check_request do |_endpoint, data, _headers|
+      assert_equal split_data, JSON.parse(data)['splits']
+    end.respond_with(successful_authorize_response)
+  end
+
   def test_execute_threed_false_with_additional_data
     stub_comms do
       @gateway.authorize(@amount, @credit_card, @options.merge({ execute_threed: false, overwrite_brand: true, selected_brand: 'maestro' }))