fix: missing unit test file

src/KafkaFlow.UnitTests/Serializers/NewtonsoftJsonDeserializerTests.cs

@@ -0,0 +1,48 @@
+namespace KafkaFlow.UnitTests.Serializers
+{
+    using System;
+    using System.IO;
+    using System.Text;
+    using System.Threading.Tasks;
+    using AutoFixture;
+    using FluentAssertions;
+    using KafkaFlow.Serializer;
+    using Microsoft.VisualStudio.TestTools.UnitTesting;
+    using Moq;
+    using Newtonsoft.Json;
+
+    [TestClass]
+    public class NewtonsoftJsonDeserializerTests
+    {
+        private readonly Mock<ISerializerContext> contextMock = new ();
+        private readonly NewtonsoftJsonDeserializer deserializer = new ();
+
+        private readonly Fixture fixture = new();
+
+        [TestMethod]
+        public async Task DeserializeAsync_ValidPayload_ObjectGenerated()
+        {
+            // Arrange
+            var message = this.fixture.Create<TestMessage>();
+            using var input = new MemoryStream(Encoding.UTF8.GetBytes(JsonConvert.SerializeObject(message)));
+
+            // Act
+            var result = await this.deserializer.DeserializeAsync(input, typeof(TestMessage), this.contextMock.Object);
+
+            // Assert
+            result.Should().NotBeNull();
+            result.Should().BeOfType<TestMessage>();
+        }
+
+        private class TestMessage
+        {
+            public int IntegerField { get; set; }
+
+            public string StringField { get; set; }
+
+            public double DoubleField { get; set; }
+
+            public DateTime DateTimeField { get; set; }
+        }
+    }
+}