diff --git a/net-users-api.Tests/Controllers/UsersControllerTests.cs b/net-users-api.Tests/Controllers/UsersControllerTests.cs
new file mode 100644
index 0000000..d0dc7a5
--- /dev/null
+++ b/net-users-api.Tests/Controllers/UsersControllerTests.cs
@@ -0,0 +1,188 @@
+using Microsoft.AspNetCore.Mvc;
+using Microsoft.Extensions.Logging;
+using Moq;
+using NetUsersApi.Controllers;
+using NetUsersApi.Models;
+
+namespace NetUsersApi.Tests.Controllers;
+
+public class UsersControllerTests
+{
+    private readonly Mock<ILogger<UsersController>> _mockLogger;
+    private readonly UsersController _controller;
+
+    public UsersControllerTests()
+    {
+        _mockLogger = new Mock<ILogger<UsersController>>();
+        _controller = new UsersController(_mockLogger.Object);
+    }
+
+    [Fact]
+    public void GetUsers_ReturnsAllUsers()
+    {
+        // Arrange
+        // The controller uses static data, so we can just call it
+
+        // Act
+        var result = _controller.GetUsers();
+
+        // Assert
+        var okResult = Assert.IsType<OkObjectResult>(result.Result);
+        var users = Assert.IsAssignableFrom<IEnumerable<UserProfile>>(okResult.Value);
+        Assert.NotEmpty(users);
+    }
+
+    [Theory]
+    [InlineData("1")]
+    [InlineData("2")]
+    [InlineData("3")]
+    public void GetUser_ValidId_ReturnsUser(string id)
+    {
+        // Act
+        var result = _controller.GetUser(id);
+
+        // Assert
+        var okResult = Assert.IsType<OkObjectResult>(result.Result);
+        var user = Assert.IsType<UserProfile>(okResult.Value);
+        Assert.Equal(id, user.Id);
+    }
+
+    [Fact]
+    public void GetUser_InvalidId_ReturnsNotFound()
+    {
+        // Arrange
+        var invalidId = "999";
+
+        // Act
+        var result = _controller.GetUser(invalidId);
+
+        // Assert
+        var notFoundResult = Assert.IsType<NotFoundObjectResult>(result.Result);
+        Assert.NotNull(notFoundResult.Value);
+    }
+
+    [Fact]
+    public void CreateUser_ValidUser_ReturnsCreatedAtAction()
+    {
+        // Arrange
+        var newUser = new UserProfile
+        {
+            Id = "100",
+            FullName = "Test User",
+            Emoji = "🧪"
+        };
+
+        // Act
+        var result = _controller.CreateUser(newUser);
+
+        // Assert
+        var createdResult = Assert.IsType<CreatedAtActionResult>(result.Result);
+        var returnedUser = Assert.IsType<UserProfile>(createdResult.Value);
+        Assert.Equal(newUser.Id, returnedUser.Id);
+        Assert.Equal(newUser.FullName, returnedUser.FullName);
+        Assert.Equal(newUser.Emoji, returnedUser.Emoji);
+        Assert.Equal(nameof(UsersController.GetUser), createdResult.ActionName);
+    }
+
+    [Fact]
+    public void CreateUser_NullUser_ReturnsBadRequest()
+    {
+        // Arrange
+        UserProfile? nullUser = null;
+
+        // Act
+        var result = _controller.CreateUser(nullUser!);
+
+        // Assert
+        var badRequestResult = Assert.IsType<BadRequestObjectResult>(result.Result);
+        Assert.NotNull(badRequestResult.Value);
+    }
+
+    [Fact]
+    public void UpdateUser_ValidUser_ReturnsUpdatedUser()
+    {
+        // Arrange
+        var userId = "1";
+        var updatedUser = new UserProfile
+        {
+            Id = userId,
+            FullName = "Updated Name",
+            Emoji = "✨"
+        };
+
+        // Act
+        var result = _controller.UpdateUser(userId, updatedUser);
+
+        // Assert
+        var okResult = Assert.IsType<OkObjectResult>(result.Result);
+        var returnedUser = Assert.IsType<UserProfile>(okResult.Value);
+        Assert.Equal(userId, returnedUser.Id);
+        Assert.Equal(updatedUser.FullName, returnedUser.FullName);
+        Assert.Equal(updatedUser.Emoji, returnedUser.Emoji);
+    }
+
+    [Fact]
+    public void UpdateUser_InvalidId_ReturnsNotFound()
+    {
+        // Arrange
+        var invalidId = "999";
+        var updatedUser = new UserProfile
+        {
+            Id = invalidId,
+            FullName = "Updated Name",
+            Emoji = "✨"
+        };
+
+        // Act
+        var result = _controller.UpdateUser(invalidId, updatedUser);
+
+        // Assert
+        Assert.IsType<NotFoundObjectResult>(result.Result);
+    }
+
+    [Fact]
+    public void UpdateUser_NullUser_ReturnsBadRequest()
+    {
+        // Arrange
+        var userId = "1";
+        UserProfile? nullUser = null;
+
+        // Act
+        var result = _controller.UpdateUser(userId, nullUser!);
+
+        // Assert
+        var badRequestResult = Assert.IsType<BadRequestObjectResult>(result.Result);
+        Assert.NotNull(badRequestResult.Value);
+    }
+
+    [Fact]
+    public void UpdateUser_MismatchedId_UpdatesWithCorrectId()
+    {
+        // Arrange
+        var userId = "1";
+        var updatedUser = new UserProfile
+        {
+            Id = "999", // Different from the route parameter
+            FullName = "Updated Name",
+            Emoji = "✨"
+        };
+
+        // Act
+        var result = _controller.UpdateUser(userId, updatedUser);
+
+        // Assert
+        var okResult = Assert.IsType<OkObjectResult>(result.Result);
+        var returnedUser = Assert.IsType<UserProfile>(okResult.Value);
+        Assert.Equal(userId, returnedUser.Id); // Should use the route parameter ID
+    }
+
+    [Fact]
+    public void DeleteUser_ThrowsNotImplementedException()
+    {
+        // Arrange
+        var userId = "1";
+
+        // Act & Assert
+        Assert.Throws<NotImplementedException>(() => _controller.DeleteUser(userId));
+    }
+}
diff --git a/net-users-api.Tests/net-users-api.Tests.csproj b/net-users-api.Tests/net-users-api.Tests.csproj
new file mode 100644
index 0000000..d0f0629
--- /dev/null
+++ b/net-users-api.Tests/net-users-api.Tests.csproj
@@ -0,0 +1,27 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFramework>net9.0</TargetFramework>
+    <RootNamespace>NetUsersApi.Tests</RootNamespace>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+    <IsPackable>false</IsPackable>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="coverlet.collector" Version="6.0.2" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.12.0" />
+    <PackageReference Include="Moq" Version="4.20.72" />
+    <PackageReference Include="xunit" Version="2.9.2" />
+    <PackageReference Include="xunit.runner.visualstudio" Version="2.8.2" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <Using Include="Xunit" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\net-users-api\net-users-api.csproj" />
+  </ItemGroup>
+
+</Project>
diff --git a/net-users-demo.sln b/net-users-demo.sln
index e9bb8f5..a8d1496 100644
--- a/net-users-demo.sln
+++ b/net-users-demo.sln
@@ -1,22 +1,48 @@
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+EndProject
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