diff --git a/Vonage.Test/Messages/Rcs/RcsMessagesTest.cs b/Vonage.Test/Messages/Rcs/RcsMessagesTest.cs
index 68c31b35..5c23e5c7 100644
--- a/Vonage.Test/Messages/Rcs/RcsMessagesTest.cs
+++ b/Vonage.Test/Messages/Rcs/RcsMessagesTest.cs
@@ -1,6 +1,7 @@
 #region
 using System;
 using System.Threading.Tasks;
+using Vonage.Common.Monads;
 using Vonage.Messages;
 using Vonage.Messages.Rcs;
 using Vonage.Request;
@@ -107,7 +108,7 @@ public async Task SendRcsVideoAsyncReturnsOk()
     [Fact]
     public async Task UpdateAsyncReturnsOk()
     {
-        this.Setup(this.expectedUri, "", this.helper.GetRequestJson());
+        this.Setup(this.expectedUri, Maybe<string>.None, this.helper.GetRequestJson());
         await this.client.MessagesClient.UpdateAsync(RcsUpdateMessageRequest.Build("ID-123"));
     }
 
diff --git a/Vonage.Test/Messages/WhatsApp/WhatsAppMessagesTest.cs b/Vonage.Test/Messages/WhatsApp/WhatsAppMessagesTest.cs
index 44bbfa52..76ad7c41 100644
--- a/Vonage.Test/Messages/WhatsApp/WhatsAppMessagesTest.cs
+++ b/Vonage.Test/Messages/WhatsApp/WhatsAppMessagesTest.cs
@@ -3,6 +3,7 @@
 using System.Collections.Generic;
 using System.Threading.Tasks;
 using FluentAssertions;
+using Vonage.Common.Monads;
 using Vonage.Messages;
 using Vonage.Messages.WhatsApp;
 using Vonage.Messages.WhatsApp.ProductMessages.MultipleItems;
@@ -515,7 +516,7 @@ public async Task SendWhatsAppVideoAsyncReturnsOkWithContext()
     [Fact]
     public async Task UpdateAsyncReturnsOk()
     {
-        this.Setup(this.expectedUri, "", this.helper.GetRequestJson());
+        this.Setup(this.expectedUri, Maybe<string>.None, this.helper.GetRequestJson());
         await this.BuildVonageClient(Credentials.FromAppIdAndPrivateKey(this.AppId, this.PrivateKey))
             .MessagesClient.UpdateAsync(WhatsAppUpdateMessageRequest.Build("ID-123"));
     }
diff --git a/Vonage.Test/TestBase.cs b/Vonage.Test/TestBase.cs
index c89158eb..1beab898 100644
--- a/Vonage.Test/TestBase.cs
+++ b/Vonage.Test/TestBase.cs
@@ -1,4 +1,5 @@
-using System;
+#region
+using System;
 using System.Collections.Generic;
 using System.IO;
 using System.Net;
@@ -12,10 +13,12 @@
 using Moq;
 using Moq.Protected;
 using Vonage.Common;
+using Vonage.Common.Monads;
 using Vonage.Request;
 using Vonage.Test.Common.TestHelpers;
 using Xunit;
 using TimeProvider = Vonage.Common.TimeProvider;
+#endregion
 
 namespace Vonage.Test
 {
@@ -73,17 +76,21 @@ private static string GetAssemblyDirectory()
             return Path.GetDirectoryName(path);
         }
 
-        protected void Setup(string uri, string responseContent, string requestContent = null,
+        protected void Setup(string uri, Maybe<string> responseContent, string requestContent = null,
             HttpStatusCode expectedCode = HttpStatusCode.OK) =>
-            this.Setup(uri, new StringContent(responseContent, Encoding.UTF8, "application/json"), expectedCode,
+            this.Setup(uri,
+                responseContent.Map<HttpContent>(content =>
+                    new StringContent(content, Encoding.UTF8, "application/json")), expectedCode,
                 requestContent);
 
         protected void Setup(string uri, byte[] responseContent, HttpStatusCode expectedCode = HttpStatusCode.OK) =>
             this.Setup(uri, new StreamContent(new MemoryStream(responseContent)), expectedCode);
 
-        private void Setup(string uri, HttpContent httpContent, HttpStatusCode expectedCode,
+        private void Setup(string uri, Maybe<HttpContent> httpContent, HttpStatusCode expectedCode,
             string requestContent = null)
         {
+            var expectedResponse = new HttpResponseMessage(expectedCode);
+            httpContent.IfSome(some => expectedResponse.Content = some);
             var mockHandler = new Mock<HttpMessageHandler>(MockBehavior.Strict);
             mockHandler
                 .Protected()
@@ -99,11 +106,7 @@ private void Setup(string uri, HttpContent httpContent, HttpStatusCode expectedC
                     var actualContent = actualHttpRequestMessage.Content.ReadAsStringAsync().Result;
                     Assert.Equal(requestContent, actualContent, StringComparer.OrdinalIgnoreCase);
                 })
-                .ReturnsAsync(new HttpResponseMessage
-                {
-                    StatusCode = expectedCode,
-                    Content = httpContent,
-                })
+                .ReturnsAsync(expectedResponse)
                 .Verifiable();
             this.configuration.ClientHandler = mockHandler.Object;
         }
diff --git a/Vonage.Test/VoiceTests.cs b/Vonage.Test/VoiceTests.cs
index fe288fd2..439ec9d6 100644
--- a/Vonage.Test/VoiceTests.cs
+++ b/Vonage.Test/VoiceTests.cs
@@ -1,14 +1,17 @@
-using System;
+#region
+using System;
 using System.Globalization;
 using System.Net;
 using System.Threading.Tasks;
 using AutoFixture;
 using FluentAssertions;
 using Vonage.Common.Exceptions;
+using Vonage.Common.Monads;
 using Vonage.Voice;
 using Vonage.Voice.Nccos;
 using Vonage.Voice.Nccos.Endpoints;
 using Xunit;
+#endregion
 
 namespace Vonage.Test;
 
@@ -456,7 +459,7 @@ public async Task UpdateCallAsync()
     {
         var uuid = this.fixture.Create<Guid>().ToString();
         var request = new CallEditCommand {Action = CallEditCommand.ActionType.earmuff};
-        this.Setup($"{BaseUri}/{uuid}", string.Empty, this.GetRequestJson());
+        this.Setup($"{BaseUri}/{uuid}", Maybe<string>.None, this.GetRequestJson());
         var response = await this.client.VoiceClient.UpdateCallAsync(uuid, request);
         Assert.True(response);
     }
@@ -470,7 +473,7 @@ public async Task UpdateCallWithCredentials()
             Destination = new Destination {Type = "ncco", Url = new[] {"https://example.com/ncco.json"}},
             Action = CallEditCommand.ActionType.transfer,
         };
-        this.Setup($"{BaseUri}/{uuid}", string.Empty, this.GetRequestJson());
+        this.Setup($"{BaseUri}/{uuid}", Maybe<string>.None, this.GetRequestJson());
         var response =
             await this.client.VoiceClient.UpdateCallAsync(uuid, request,
                 this.BuildCredentialsForBearerAuthentication());
@@ -486,7 +489,7 @@ public async Task UpdateCallWithInlineNcco()
             Destination = new Destination {Type = "ncco", Ncco = new Ncco(new TalkAction {Text = "hello world"})},
             Action = CallEditCommand.ActionType.transfer,
         };
-        this.Setup($"{BaseUri}/{uuid}", string.Empty, this.GetRequestJson());
+        this.Setup($"{BaseUri}/{uuid}", Maybe<string>.None, this.GetRequestJson());
         Assert.True(await this.client.VoiceClient.UpdateCallAsync(uuid, request));
     }