Enhance transfer functionality by adding idempotency key validation and currency support

src/CheckoutSdk/Transfers/TransferSourceRequest.cs

@@ -1,9 +1,13 @@
-namespace Checkout.Transfers
+using Checkout.Common;
+
+namespace Checkout.Transfers
 {
     public class TransferSourceRequest
     {
         public string Id { get; set; }
 
         public long? Amount { get; set; }
+
+        public Currency? Currency { get; set; }
     }
 }

src/CheckoutSdk/Transfers/TransfersClient.cs

@@ -14,10 +14,10 @@ public TransfersClient(IApiClient apiClient,
         }
 
         public async Task<CreateTransferResponse> InitiateTransferOfFunds(CreateTransferRequest createTransferRequest,
-            string idempotencyKey = null,
+            string idempotencyKey,
             CancellationToken cancellationToken = default)
         {
-            CheckoutUtils.ValidateParams("createTransferRequest", createTransferRequest);
+            CheckoutUtils.ValidateParams("createTransferRequest", createTransferRequest, "idempotencyKey", idempotencyKey);
             return await ApiClient.Post<CreateTransferResponse>(TransfersPath,
                 SdkAuthorization(),
                 createTransferRequest,

test/CheckoutSdkTest/Transfers/TransfersClientTest.cs

@@ -35,7 +35,7 @@ public async Task ShouldInitiateTransferOfFunds()
                     createTransferRequest, It.IsAny<CancellationToken>(), It.IsAny<string>()))
                 .ReturnsAsync(createTransferResponse);
 
-            var response = await _transfersClient.InitiateTransferOfFunds(createTransferRequest);
+            var response = await _transfersClient.InitiateTransferOfFunds(createTransferRequest, "idempotency-key");
 
             response.ShouldNotBeNull();
             response.ShouldBe(createTransferResponse);

test/CheckoutSdkTest/Transfers/TransfersIntegrationTest.cs

@@ -1,3 +1,4 @@
+using Checkout.Common;
 using Shouldly;
 using System;
 using System.Threading.Tasks;
@@ -19,7 +20,7 @@ private async Task ShouldInitiateAndRetrieveTransferOfFunds()
             var createTransferRequest =
                 new CreateTransferRequest
                 {
-                    Source = new TransferSourceRequest {Amount = 200, Id = "ent_kidtcgc3ge5unf4a5i6enhnr5m"},
+                    Source = new TransferSourceRequest {Amount = 200, Id = "ent_kidtcgc3ge5unf4a5i6enhnr5m", Currency = Currency.GBP},
                     Destination = new TransferDestinationRequest {Id = "ent_w4jelhppmfiufdnatam37wrfc4"},
                     TransferType = TransferType.Commission
                 };
@@ -40,6 +41,8 @@ private async Task ShouldInitiateAndRetrieveTransferOfFunds()
             transferDetailsResponse.RequestedOn.ShouldNotBeNull();
             transferDetailsResponse.Source.ShouldNotBeNull();
             transferDetailsResponse.Source.EntityId.ShouldNotBeNull();
+            transferDetailsResponse.Source.Amount.ShouldBe(200);
+            transferDetailsResponse.Source.Currency.ShouldBe(Currency.GBP);
             transferDetailsResponse.Destination.ShouldNotBeNull();
             transferDetailsResponse.Destination.EntityId.ShouldNotBeNull();
         }
@@ -50,7 +53,7 @@ private async Task ShouldInitiateTransferOfFundsIdempotently()
             var createTransferRequest =
                 new CreateTransferRequest
                 {
-                    Source = new TransferSourceRequest {Amount = 100, Id = "ent_kidtcgc3ge5unf4a5i6enhnr5m"},
+                    Source = new TransferSourceRequest {Amount = 100, Id = "ent_kidtcgc3ge5unf4a5i6enhnr5m", Currency = Currency.GBP},
                     Destination = new TransferDestinationRequest {Id = "ent_w4jelhppmfiufdnatam37wrfc4"},
                     TransferType = TransferType.Commission
                 };